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Messages - TomT

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1
Programs & Speakers / 240301 SBAU meeting slides Powerpoint file attached
« on: February 29, 2024, 11:42:17 PM »
For our March 2024 meeting, the 10 slide PowerPoint file attached here can be downloaded and played on your computer
update 3-1-24: modified PP for added Secretary statement on joining, slide 9.

2
Programs & Speakers / 240202 SBAU 1st Fri Powerpoint file
« on: February 01, 2024, 07:37:34 PM »
download the attached 35MB file and open/run it for review

3
Programs & Speakers / 240105 SBAU intro powerpoint file attached
« on: January 05, 2024, 04:35:51 PM »
see January 2024 SBAU intro powerpoint for your review, 34MB

4
Please download (45MB, so be patient), open the file (double-click?, there should be an application on your computer to handle this, or an offer to download a program might be seen) and then review the slides.
This is the SBAU greeting screens, business and Outreach review, and speaker introduction.
JohnW will activate the powerpoint and only the right/left arrows on the laptop should be needed to switch the slides.
Please stay at the podium in front of the laptop camera for our Zoom members to see you.
The speaker's powerpoint will be activated after this, either on the same podium laptop or their own, which will take a few minutes.

5
Club Miscellaneous / 231014 planning meeting audio file attached
« on: October 19, 2023, 12:47:50 AM »
see attachment of mp4 audio file, and the unfinished transcript docx file. 



6
see attached powerpoint 51 slides, draft, needs verification by David

7
see attached powerpoint file 30MB

8
Club Miscellaneous / 230909 SBAU Planning Meeting audio file and transcript
« on: September 10, 2023, 07:33:23 PM »
This is for Acting Secretary TessaF to Download attached September 9, 2023 SBAU Planning Meeting audio file and the edited transcript generated by Microsoft 365 Word Live version...pretty amazing, but does add extra lines and is not 100% accurate.  TessaF is Acting Secretary and will be generating a more condensed Meeting Minutes and Action Items.  Secretaries Pat and ChuckMcP are on vacation.

TessaF, the transcript is in two columns of size 8 font.  You might modify that to be able to see it better!  Also,to ease your viewing, perhaps determine where topics change and put some sort of break at those points and perhaps a sub-heading using the topic title?

The 1GB video is available as well, but only if you are desperate to see it would I post that somewhere.
TomT

9
Download the Word doc attachment to this topic to see a properly formatted and with highlighted modifications from the 14 July 2017 Agreement.

Here is President Jerry's draft in plain text without the formatting and without highlighted changes:

AGREEMENT between the
Santa Barbara Astronomical Unit
and the
Santa Barbara Museum of Natural History
14 July 2017
Updated 28 June 2021


Whereas the Santa Barbara Astronomical Unit (SBAU) was founded in 1984 with a mission to inform its members and the general public about astronomy and to promote awareness of astronomy related events and activities in and around Santa Barbara County; and

Whereas as an essential part of its mission to inspire a passion for the natural world, the Santa Barbara Museum of Natural History (“SBMNH” and “Museum”) provides a robust space sciences program consisting of exhibitions, a Planetarium, an Observatory, and numerous programs for both school groups and adult visitors,

Whereas the SBAU and SBMNH have worked in close collaboration to promote interest and education in astronomy. 

Therefore, the SBAU and SBMNH agree to memorialize their collaboration in this Agreement.

SBAU agrees to:

•   Serve as an affiliated organization of SBMNH and inform the Museum of its planned educational and outreach activities.
•   Provide workshops, star parties and other educational activities (as listed in the next section and amended from time to time as agreed to by both organizations) both on and off the Museum campus as an affiliated organization and include the Museum name and logo on promotional fliers and event signage as agreed to by the representatives of the SBAU and SBMNH.
•   When on the Museum campus, comply with all conditions outlined in the Museum’s Conditional Use Permit and other agreements that have been negotiated between the Museum and the City of Santa Barbara. Particular attention will be given to the hard stop of all programs and activities by 10:30 p.m. and all participants shall vacate the site by 11:00 p.m.; and to ensuring a low noise level be maintained by SBAU members and guests on the Museum’s grounds both during programs and when leaving the site.
•   Both on and off Museum property, comply with all rules for staff and volunteers and with SBMNH standards of conduct developed to ensure an excellent visitor experience. SBMNH will provide the necessary guidelines to SBAU.
o   In order to ensure the safety of minors and all of the public the SBAU interacts with and fulfil the requirements of the Museum’s insurance policy, all SBAU outreach volunteers shall review and sign the Museum’s Volunteer handbook and Code of Conduct, as well as pass the standard background check that the Museum uses for other volunteers.
•   Both on and off Museum property, comply with all health and safety rules adopted by the Museum, including taking all necessary preventative actions against infectious diseases.

SBMNH agrees to:

•   Serve as the home and sponsor of the SBAU
•   Assign a member of its professional staff (typically this is the Museum’s Astronomy Programs staff member) as the primary liaison with the SBAU and their designated liaison.
•   Serve as the fiscal agent for the SBAU, provide accounting for SBAU funds, receive and disperse funds on behalf of, and as directed by, the SBAU in accordance with the Museum’s policies related to its service as a fiscal agent.
•   Extend the Museum’s liability insurance coverage for all SBAU events held on or off Museum property. With advanced notice, SBMNH will work with its insurance broker to provide copy of insurance policy, referencing the scope of coverage.
•   Provide real and virtual space at the Museum for various SBAU meetings and activities as mutually agreed to at no cost. Currently SBAU activities that take place at the Museum include:
o   Dedicated, secure storage space for SBAU telescopes and equipment; The Museum will keep keys to access this secure space in the event of an emergency.
o   Monthly telescope building workshop
o   Monthly business meeting of the SBAU
o   Use of the Observatory and adjacent plaza for monthly Star Parties open to the public at no cost
o   Annual membership for virtual meeting space such as Zoom or similar services
o   Use of the Planetarium for shows as mutually agreed to by the SBAU and SBMNH
o   Other educational activities and programs which are agreed to on a case-by-case basis
•   Train and provide access to designated SBAU members so that they may operate the Marschak Telescope in the Palmer Observatory and the Digistar 5 projection system in the Gladwin Planetarium.
•   Promote SBAU activities on the Museum’s marketing and outreach materials (media, print, and digital) where possible with review by an SBAU representative before distribution.

SBAU and SBMNH further agree that:

•   Any proposed SBAU fundraising activities will be agreed to by both parties in advance.
•   Any SBMNH fundraising activities directed toward SBAU members will be discussed with an SBAU representative prior to enactment of said activities.
•   Sale of SBAU branded merchandise sold at cost to members will not require review by SBMNH.
•   Expenses associated with the repair and maintenance of dedicated SBAU storage space will be shared between the SBAU and SBMNH as agreed to on a case-by-case basis.
•   All SBAU flyers, brochures, and exhibit signage used on the SBMNH campus are subject to approval by SBMNH.
•   From time to time, disagreements may arise between the parties.  The first step in resolving disagreements will be between the individuals who have the disagreement. The final step in resolving disagreements will be between the Presidents of the two organizations.  The joint decision of the Presidents will be final.
•   On a regular basis, representatives of the two organizations will have a coordination meeting to review how the partnership and the programs are working in terms of coordination and logistics.  On a periodic basis this agreement will be reviewed and amended as needed.

Force Majeure: Both organizations understand that circumstances beyond our control may affect the ability of either party to fulfill the agreement under this MOU. 

This Agreement may be terminated by mutual agreement of both parties.


For SBAU:   For SBMNH:

____________________   ____________________

____________________   Luke J. Swetland
   President & CEO

____________________   ____________________
Date   Date



10
see attached files for more great insights
Ophiuchus and the Rod of Asclepius area of the sky
and
Comments on Astrophotography

11
Beginners Imaging / JerryW list of astrophotography steps
« on: November 22, 2021, 12:23:29 PM »
On Fri, Nov 19, 2021 at 9:06 PM Jerry wrote:

    Hi Tom
    I listed the steps I go through to set up a portable scope for imaging. I can go over it at Tuesdays meeting.

    Steps to setup a portable Astro-imaging session


        Set up tripod and mount before dusk and roughly align with North using a compass. Be sure to compensate for the difference between true and magnetic north.
        Using a polar scope in the polar axis of the mount, complete alignment to true north by aligning the image of Polaris with it’s location on the scopes reticle for the correct latitude and time.
        Mount the telescope and counterweights, and balance the scope in both axes
        Align the finder scope with the main scope using a bright star and securely lock the finder scope in place.
        Using the finder, visually center a bright star.
        Put the camera in and focus, using a Bahtinoff mask, on the image of the star.
        REMOVE THE BAHTINOFF MASK!!!
        Inform the planetarium program (e.g. The Sky X) the name of the current star.
        Go to the first target of the evening.
        Take a few quick frames to frame the object in the FOV.
        Set the camera control on the desired number and duration of subframes. Usually 12 exposures at 6 minutes each.
        In PHD Guiding, identify a guide star that will track with a 1 second exposure.
        Calibrate each axis, engage dithering with the camera control software.
        Start the capture sequence.
        Listen to my ipod.


    This is the sequence I have used for the past two decades with Astro-Physics mounts (900, 1200 and 1600), QSI wsg type cameras with integral guide chip (500 and 600 series cameras), and DSLR Canon 20Da, 50DH and 60Da. Software is Nebulosity 4 and PHD 2 from Craig Stark. Power is from deep cycle batteries.The planetarium software is The Sky 6 and X. Processing is done using CCDStack, Mira Pro 7, and PhotoShop 6.

    Jerry

12
"Going beyond the Veil", a great, 9 page, 3MB, explainer of the objects in the sky near Cygnus the Swan constellation is attached.

13
General Observing / 210415 image processing steps simplified
« on: July 09, 2021, 10:27:39 PM »
On 4/15/2021 1:49 PM, Jerry wrote:
> Hi Tom
>
> The major steps of image processing are:
> Calibration
> Stacking
> Stretching
>       First linear stretching using “levels”
>       Then non linear stretching using “curves”
> Adjust color
>
> Hope that helps, Jerry
>
> Sent from my iPad

14
On 4/15/2021 1:11 PM, Jerry wrote:
> Hi Tom
>
> Here’s an overview of image processing I sent to Tim earlier.
>
> At last weeks telescope workshop you said you’d like to see a simple list of what image processing consists of. So here’s an overview.
>
>
> First there is the object in the sky that you want to take an image of. Let’s say it’s M42. So you attach your camera to your telescope, focus it and point it at the object and take a picture.
>
>
> You have now taken a picture that includes M42, but you also took a picture of a number of other things too. These other things must be removed so you are left with a picture of only M42.
>
>
> These other things you imaged are:
>
> 1 Light reflected from the sky, including gradients;
>
> 2 Other objects in the sky
>
>    airplanes
>
>    meteors
>
>    satellites
>
> 3 Scattered light in the telescope
>
> 4 Diffraction effects
>
> 5 Vignetting
>
> 6 Optical aberrations
>
> 7 Dust
>
> 8Tracking errors
>
>    uncorrected periodic errors in your telescope drive and wind.
>
> 9 Variation in dark current from pixel to pixel across the focal plane (non optical generated current, exponentially dependent on camera temperature)
>
> 10 Variation of gain between each preamp channel in the cameras electronics.
>
>
> Numbers 1, 3, 4, 5, 6 and 7 can be imaged by themselves, called a flat frame, and subtracted using software from your raw image. There are a number of ways to take a flat frame. The idea is to have your camera attached to and oriented with the telescope and in-focus exactly the same way it was you took your astrophoto and the use that setup to take a picture of a uniform, gradient free field. Getting that field is the greatest challenge of flat framing.
>
>    The first way I learned to get a white field is to stand next to your telescope while it’s in a horizontal position and then put a large piece of white poster board in front of the scope so the scope cannot see around it, then, wearing white shirt shine a flashlight on yourself. The light will shine off you and onto the poster board and then into the telescope.
>
>    You can also make or buy a light box that fits on the end of your scope.
>
>    A picture of the sky at about 50 to 60 degrees above the horizon during dusk, but before any stars come out will also due.
>
>    And finally there is software that can remove some of the common gradients. But the software will not remove dust donuts.
>
>    We’ll get to number 2 later.
>
>
> Number 9 is captured in single frame called a dark frame. This image is taken by putting the lens cap on your camera so no light can get in and taking a picture at exactly the same exposure time, ISO setting for CMOS (or gain for CCD), and focal plane temperature. Focal plane temperature is by far the most important parameter to control, since dark current is exponentially dependent on temperature.
>
>    This is the hardest thing to control is DSLRs as the focal plane temperature varies with camera use. The processing electronics generates heat and light.
>
>    For DSLRs I find a “Bad Pixel Map” works better than a dark frame.
>
>
> Number 10 is captured in a single picture called a “bias frame’. To take a bias frame put the lens cap on your camera and take a picture at the fastest shutter speed available. This will capture a map of the variation of electronic gain over the entire focal plane.
>
>
> Number 2 and 8 are handled in a different manner, through stacking subframes. For many reasons it’s better to take many subframes instead of one single picture. Suppose you wanted a one hour picture of M42. You could hold the shutter open for one hour but it’s better to take twelve 5 minutes or sixty 1 minute subframes and add them, called stacking. Errors like 2 and 8 will occur differently on each subframe. Many, like a meteor, will only occur on one subframe. In stacking, anything that is unique to one subframe compared to the ensemble of subframes will be eliminated.
>
>
> None of these images errors vary in time all are fixed. Except of course for meteors and such. Since these image artifacts do not fluctuate in time on a scale we can notice they are not technically noise. But amateurs, even amateur magazines refer to them as noise. Unless your trying to write image processing algorithms or talk about image processing to a scientist, it’s OK to refer to them as noise. It’s just something you want to get rid of.
>
>
> In summary your Raw image of M42 will actually be an image of M42 plus a bias frame and a flat frame and a dark frame. Every picture you take with your camera will have a bias frame. When you take a dark frame or a flat frame, they will also have a bias frame in them. In addition to a bias frame, a flat frame also contains a dark frame. The software you use to calibrate your photos will keep everything straight for you.
>
> Sent from my iPad

15
General Observing / 210406 how to measure light curves for supernova?
« on: July 09, 2021, 10:23:55 PM »
On 4/6/2021 4:59 PM, TomCez wrote:
> JerryW & all,
> How do astronomers precisely measure the light curves (magnitude, relative flux?) for supernovas (and variable stars), which I would think would tell them what type of supernova is taking place?   I guess this might be the best answer to my question:  https://lco.global/spacebook/telescopes/what-is-photometry/  :
>
> "When measuring the brightness of an object or objects over several images taken over time, comparison stars must be used. By using a comparison star or stars, variation in brightness that can be caused by sources such as the atmosphere is removed. For example, if over the course of several exposures, a thin cloud passed over the telescope, the brightness of all of the stars in the image would be decreased by a similar amount. By using comparison stars, effects like these are divided out. Comparison stars that are of similar brightness to the target star, not very close to other stars, and not near the edge of the frame make the best choices. Astronomers usually compare the comparison stars, and don't use ones that are variable stars."
>
> Also, https://lco.global/education/activities/plotting-a-supernova-light-curve/
>
> I still do not get how they do it extremely precisely to parts per million of a magnitude or better...counting photons hitting a pixel of a camera sensor?  And what is the exact standard magnitude star to start from, Vega = 0.0000000?  For all wavelengths?  Seems like a lot of work involved to get all the stars rated!
>
> TomT

16
Newtonian Telescopes / 210313 HenkA GSO newtonian
« on: July 09, 2021, 09:39:00 PM »


On 3/14/2021 11:54 AM, Henk Aling wrote:
> The only reason why I align the guide scope with the OTA is because I can’t plate-solve with my best imaging camera, a Fuji X-a1.  And even if I would use my modified 450D instead that I can control, it’s not as spiffy as the QHY5 of the Orion SSAG.  Once I get my ASI2600MM I will use it for alignment using plate solving.

> I’m sure a laser pointer will work very well and is easy to use but I vowed to myself to never use one because of the unknown risk to airplanes.

> My GSO has screws to attach a dovetail at the top but then I would need more counterweights especially because of the larger radius.  If I had looked better and noticed that the GSO was 15 lbs. heavier than an aluminum alternative it would not have been that bad.  The steel may be stiffer though so that’s an advantage.  GSO also mentioned it’s better for temperature adjustments.

> When I saw it was a GSO product I assumed it was good based on my experiences with GSO products.  They included a little cheap looking finder scope that turns out to be quite nice optically.  I may try to convert that to a guide scope.  The eypiece screws in with plastic thread.  I’m sure I can drill into the plastic and attach a sensor to it.


> From: bkm
> Sent: Saturday, March 13, 2021 7:39 PM
>
> Subject: Re: My homebuilt 12.5 inch astrograph at CalStar

> Henk,
>
> I like your wood block addition to the lower dovetail rail.  Makes for easy and secure mounting!  When I mount the C11 on the Orion Atlas Pro equatorial mount, I have a black ink line placed on the C11 white Naugahyde sleeve that lines up with a mark on the mount, which I can easily see when I attach the scope.  Your wood stop seems better, and I may try that method.  it also seems more secure (less wobbly) during the attachment.
>
> Some Dobsonian mounting rings have saddles both top and bottom.  Obviously, yours has them on the bottom where the dovetail plate attaches.  If they are present on the top also, you can mount another dovetail plate there to which you can attach your guide scope.  It will always be aligned.
>
> The C11 has dovetail plates both top and bottom.  The finder scope mounts to the upper dovetail plate.
>
> I've also added a curved 1/8" thick aluminum plate to the top of the scope that mounts to existing tapped holes in the C11 OTA rear casting.  I've drilled and tapped holes in that new plate to which dovetail shoes are attached.  Among other things, I attach a laser finder to one of the dovetail shoes.  This addition makes alignment really easy.  The laser pointer is already collimated to the scope.  I swing the scope around in RA and dec to have the laser pointer point at the desired object.  When I look in the finder scope, the object is in view, and I only have to center it.  lastly, I center it in the eyepiece of the main scope.  After two stars, the alignment is complete.
>
> Bruce
>
>
> On 3/13/2021 4:52 PM, Henk Aling wrote:
>> Well here’s my setup that I will try tonight.
>> 
>> I have added a wooden stop underneath the Losmandy dovetail.  There was a screw hole already so all I had to do was cut the wood to the right size so it is balanced, shorten the screw that I found, drill a hole and screw it in.  I only have to make a power push to lift the scope on the mount, flip it down so the stop holds it, then tighten the screws.  Not too hard really, it’s only 48 lbs. and when I grab it at both sides it’s easy to carry.  I can still see the DEC level with the stop on.
>> 
>> I fixed the counterweight problem by making an adapter for my guide scope to fit at the bottom of the counterweight bar.  It doubles as a stop for the two other weights.  It balances perfectly, there is more space to push the weights out if I have to.  Over all it is better for balancing than putting a guide scope on top of the OTA.
>> 
>> I line up the guide scope to the OTA by pushing a glass fiber tent pole segment against the base of the guide scope shoe and eyeball if it lines up with the OTA.  Should be pretty accurate.  Keep in mind that for now I need to use my guide scope for plate solving so long as I don’t have my ASI2600MM yet, so it needs to be lined up.
>> 
>> I installed Astroberry on my Pi 4B with 8 GB and it looks great.  I have not yet hooked it up but maybe I will, tonight.  One problem is that it is powered by USB-C and I want it to be powered by a 12 V cigarette lighter socket.  I can use the power adapter that came with it for now if I add an extension cord.
>> 
>> I figured out how to an old Boost cell phone as a web cam and view it through a web browser through the LiveDroid app.  It will be fun to watch the scope move from my computer.  If I want smooth video I need to hook up an ethernet cable.  The Pi is powerful enough but the Wifi dongle is slow.


17
Video and CCD Equipment / 210609 iso invariance discussion
« on: July 09, 2021, 04:55:17 PM »
On 6/10/2021 6:06 PM, bkm wrote:
> Mike,
> Thanks for reminding me of the avalanche photodiode, and your nice explanation.
> Like you, its been many years since I used them (I've been retired 32 years).  They are fast and sensitive, but excess noise is a problem.  Wikipedia has a nice writeup: https://en.wikipedia.org/wiki/Avalanche_photodiode
> In a camera detector, it is the capacitance of the photodiode that converts the photoelectric electrons to a voltage (V = Q/C).  This process is often referred to as filling the well, and when the well gets full, the pixel saturates (a voltage problem).
> Let's keep dreaming!
> Bruce
> They talk about poisson
>
> On 6/10/2021 1:21 PM, Mike Chibnik wrote:
>> That along with a new development on a new type of imaging sensor which is supposed to be more sensitive than what we have today.  Evidently they were stating something similar to avalanche diode technology.  It’s something they’ve been doing with fiber optics for a long time and we had used them at Canoga Perkins back in 2000.  With normal photo diodes one photon gets converted into 0.2 to 0.9 electron .    This number is referred to the detector’s quantum efficiency.  Avalanche diodes utilize an additional mechanism were the initial electron is accelerated in an electric field by a high voltage applied to it. As a result additional electrons are generated effectively amplifying the detected optical input.  It’s been 20 years so I’m fuzzy one the gain but as I remember it was from about 20 to 1000 depending on the construction and operating voltages which were around 100 volts.  These diodes were super expensive and tricky to use.  They were also a bit noisy.  In contrast nearly all optical sensors are photovoltaic sensors which in simplistic terms uses photons to generate a current of electrons which generates a charge that becomes a voyage which is the signal that is detected.  If it took about 20 years to combine one expensive photo diode in to a chip with millions of inexpensive high performance devices then it shouldn’t be to unreasonable to assume that this will happen with avalanche photo diode technology. 
>> I think history with image sensors will repeat itself as something very similar happened to television camera tube in the early fifties when the old Iconoscopes were replaced by the more sensitive image orthicons.
>> So it might be possible in the future where people will hold up a thick version of what might look like an iPad which will have that new optical technology with sensor technology to view the heavens.
>> We can dream can’t we?
>> Mike
>>
>>> On Jun 10, 2021, at 12:17 PM, Robert C R wrote: 
>>> Thanks, Chuck...Wow!  This looks like transformative stuff when it comes to optics.  Amazing to watch how discoveries like this will affect the world of photography and telescope optics.  We do live in amazing times!
>>> Bob R.
>>>
>>> From: macpuzl
>>> To: Bruce M
>>> Cc: Jerry W Mike C; Web Master <webmaster@sbau.org>; Ron H; Tom W; Tom T; Bob R; Dick B
>>> Sent: Thu, Jun 10, 2021 12:00 pm
>>> Subject: Re: camera iso invariance
>>> Bruce (et al) -
>>> This may be interesting:
>>> https://phys.org/news/2021-06-goodbye-camera-miniaturized-optics-counterpart.html
>>> Hasta nebula - Chuck

On 6/10/2021 3:06 AM, bkm wrote:
> Jerry,
> I forgot to mention that I also use the hat trick.  I have a piece of cardboard that is flat black painted on both sides.  I hold it in front of the telescope (not touching) when I remote trip the shutter, count to 2, then lift the cardboard away.
> The "hat trick" name arises from old time photographers who used their hat to block the camera lens as they were manually releasing the shutter on the longer time exposures needed for ordinary photography of the day (iso 25 film, or less).
> Bruce
>
> On 6/10/2021 2:37 AM, bkm wrote:
>> Thanks Jerry,
>> Accidental dithering is an apt description!
>> I normally take astrophotos with the mirror locked up, use a 2-second shutter delay, and use a remote trip
>> If I average 10 or more images in Deep Sky Stacker, I don't see pattern noise, but do see non pinpoint stars due to atmospheric turbulence.  Brighter stars are bigger smeared circles.
>> Nikon went all out with the D500 shutter.  It and the mirror holder are made from carbon fiber.  The camera can take 10-pictures per second for a 200 frame interval before it slows down.  Between each frame, it does an autofocus and an exposure calculation.  Both autofocus and exposure require the mirror to be down.
>> I know that this fast frame rate is not used in astrophotography, but the very light components should minimize shutter shake, especially if I use the quiet shutter release mode.
>> My images are usually non guided.  Typically 30 second exposures, or less.
>> Thanks for the info.  It gives me a lot of food for thought.
>> Bruce
>>
>> On 6/9/2021 6:17 PM, Jerry wrote:
>>> Bruce
>>> I depended on the accidental dithering provided by the environment, until I realized it really indicated a weakness in my set up. When I went to non DSLR cameras which did not provide a mechanical shutter shock, my dithering disappeared and my images went down the tubes.
>>> I now do dithering on purpose using software designed for it, Nebulosity and PHD Guiding working together. It gives me better control of my imaging.
>>> Jerry
>>>
>>>> On Jun 9, 2021, at 5:51 PM, bkm < wrote:
>>>> Mike,
>>>> Thanks for the reminder.  I figured that the minute movement of the image between pictures (turbulence, wind, etc.) coupled with the small sensor pixel dimensions (microns), pretty much guarantees the same Bayer filtered pixels will not overlay from one exposure to the next.  When I use Deep Sky Stacker, the pattern noise generally disappears.
>>>> Regarding your other email on dynamic range, the same website has other displays that might interest you.  See: https://www.photonstophotos.net/Charts/PDR_Area_scatter.htm
>>>> You can turn off the various camera manufacturers  colored symbol by clicking on them in the legend.  I find my Nikon D500 and D5200 have very similar dynamic ranges, and are among the best.
>>>> Bruce
>>>>
>>>> On 6/9/2021 2:48 PM, Mike Chibnik wrote:
>>>>> Hi Bruce:
>>>>> The way you get around the issue with fixed pattern color noise is to use dithering.  My friend Mark said that the best way he found was to dither for every single exposure.  Otherwise he found out that there was not enough randomization.
>>>>> Mike

Hi Bruce:
I went to the website and plugged in the dynamic range page for various cameras I had/have in addition the the RA which is Canon's latest Astroimaging camera.
It appears that dynamic range increases as ISO is reduced.  However, this might result in losing faint nebulosity.  However, if you want to image colors best for objects like colorful globulars or the Orion Nebula then to me it appears a lower ISO is the way.
image.png
Mike

On Wed, Jun 9, 2021 at 11:03 AM bkm > wrote:
    Jerry and Mike,
    Thanks for your responses.  I look forward to more information you might
    find.
    Jerry,  yes, fixed pattern noise in color pictures can be a problem with
    Bayer interpolation.  I've noticed it.  When Deep Sky Stacker averages a
    number of photos, the fixed pattern noise appears to be much reduced.
    Probably caused by the images not being aligned exactly on the sensor, a
    good thing.
    Bob Richard has noticed and complained about this artifact in his
    pictures with the Atik cameras he uses.
    Bruce

    On 6/9/2021 10:43 AM, Mike Chibnik wrote:
    > Thanks Bruce
    > I was going over other websites afterwards and found links in some
    > sites where they refer to others that have differing findings.  I’m
    > led to believe that as technology changes certain aspects such as read
    > noise, dark noise, pixel size and quantum efficiency have lead to
    > differing optimum solutions.
    > Mike
 
    >> On Jun 9, 2021, at 10:10 AM, Jerry  wrote:
    >> Hi Bruce
    >> It’s an interesting article, thanks. The author is comparing dynamic
    >> range to photon noise and uses the proper physics definition of
    >> noise. Usually when astro imagers talk about noise in DSLRs they
    >> really mean fixed pattern noise which spatial nonuniformity. He does
    >> not address that aspect, at least at my first read. I’ll take a
    >> deeper look when I get some time.
    >> Jerry

    >>> On Jun 9, 2021, at 2:54 AM, bkm wrote:
    >>>  In today's telescope workshop, I related there was a website
    >>> showing digital camera iso invariance i.e., the signal to noise is
    >>> the same over a wide iso range.  See:
    >>> https://www.photonstophotos.net/Charts/PDR_Shadow.htm#Nikon%20D500
    >>> For the D500 I have, which has a Sony sensor, is iso invariant from
    >>> iso 400 to iso 102400.  This fact is refreshing to know, in that I
    >>> can shoot pictures at higher isos and faster shutter speeds and not
    >>> worry about noise.
    >>> The Canon 6D that astrophotographers like to use is not iso invariant.
    >>> Notice the vertical axis scale is logarithmic.
    >>> Even though the camera names are grayed out, you can select other
    >>> cameras to see their input-referred read noise vs. iso
    >>> Here are the plots from the above website:
    >>> <sensor nosie collage.jpg>
    >>> Enjoy,
    >>> Bruce

18
Tim C. Articles / Pelican case repair; plastic repair
« on: June 06, 2021, 01:46:54 PM »
> On Jun 6, 2021, at 8:58 AM, bkm wrote:
> Tim,
> Thanks for the information.
> I have carbon fiber cloth which I use to repair broken plastic parts.  I glue the part back together with super glue to temporarily hold it in place, then I weld the broken plastic part back together using a soldering iron.  Then I use a large soldering iron to melt carbon fiber strands into the plastic surface all the way around.
The repair is stronger than was the part originally.
> Because the carbon fiber is black and the plastic is generally black, the repair is nearly invisible.
> I buy carbon fiber cloth at Fiberglass Hawaii in Ventura (https://shop.fiberglasshawaii.com/).
> Bruce
>
>
> On 6/6/2021 8:29 AM, Tim Crawford wrote:
>> In any of you have the pelican cases for eye pieces or any of your gear:
>> One of my latches on my 1400 case broke. I contacted Pelican company. They wanted me to send images of the case number and latch damage . For $10 shipping they sent two new latches and pins. Ask them for instructions on replacement and they will send you instructions via email.
>> On my case, it required I drill holes through the handle to allow access to the pins. On the 1400, they want you to drill a 1/8” hole opposite the pin axis. But, in my case I drilled the first hole about 1/4” so I could “ pivot” the 1/8” drill bit to open the hole for the pin.
>> It’s a pretty easy operation and makes the case go a whole lot further! On newer cases, the access to the pins is much easier. You just tap out the pins and tap in the new latch and pins- that easy.
>> Tim

19
Here are some weblinks and part of Jerry's agenda for the show.  Download and play the attached file for the audio.  Youtube link:  https://youtu.be/B_ah0YYtPWY

May possibly make this hour live in the future on Youtube if we can set up the permissions correctly

March 1, 2021 Santa Barbara Astronomical Unit Astronomy Video Podcast weblinks:
https://www.sbau.org/ is our home page, with lots of links and info
New York Times, Exploring the Solar System--various missions listed, By Jonathan Corum, Updated July 30, 2020: 
https://www.nytimes.com/interactive/2020/science/exploring-the-solar-system.html
Scientific Psychic Interactive Moon Map--shows major near side areas with identification:
https://www.scientificpsychic.com/etc/moonmap/moon-map.html
Far side of the Moon:
https://www.publicdomainpictures.net/pictures/190000/velka/moon-far-side.jpg
The Sky Live 3D Solar System Simulator -- excellent interactive, moveable layout of the solar system.  Go to the objects listed in their menus and click on "information", scroll to bottom of the object's info page and quite often there is a 3D interactive map. 
https://theskylive.com/3dsolarsystem
Sizes of large telescopes, including Hubble and James Webb and beyond:
https://i.insider.com/5b76f354e361c037008b5083?width=1759
James Webb telescope will be placed at the L2 Lagrangian point: 
https://upload.wikimedia.org/wikipedia/commons/thumb/8/88/Lagrange_points.jpg/1200px-Lagrange_points.jpg
SpaceX Starlink satellite internet constellation:
https://en.wikipedia.org/wiki/Starlink
View of the 26,000 year circle of stars that the Earth's North Celestial Pole points to:
https://astronomy.com/-/media/Images/News%20and%20Observing/Ask%20Astro/2012/09/Earths-spin-axis.jpg?mw=600
NASA Solar System Dawn Mission to Vesta & Ceres:
https://solarsystem.nasa.gov/missions/dawn/overview/
The Sky Live 3D map of Asteroid 4 Vesta:
https://theskylive.com/3dsolarsystem?obj=vesta
The Sky Live 3D map of 1km wide Asteroid (NEO) 231937 flying by Earth on March 21, 2021:
https://theskylive.com/3dsolarsystem?obj=231937
Spaceweather shows the Sun conditions and asteroid encounter distances & size:
https://spaceweather.com/
Nice layout with Orion area nebulas identified:
https://eastexastronomy.blogspot.com/2010/08/orion.html
NASA’s Perseverance Has a Mars Rover Family Portrait: 
https://www.extremetech.com/extreme/320356-nasas-perseverance-has-a-mars-rover-family-portrait
Mars 2020 mission parachute secret decoded:
https://people.com/human-interest/nasa-reveals-secret-message-hidden-on-mars-rover-parachute/
Chinese mission to Mars, Tianwen-1: 
https://en.wikipedia.org/wiki/Tianwen-1
Emirates Mars Mission is by United Arab Emirates Space Agency: 
https://en.wikipedia.org/wiki/Emirates_Mars_Mission

More Santa Barbara Astronomical Unit videos:
https://www.youtube.com/channel/UCU0r4RxzoyT_pwNcfN5aJsA/videos


Jerry's agenda for the show, abbreviated:
This Week
  The full Moon occurred in the wee small hours of the morning last Saturday. As February’s Full Moon, it’s also known as the Snow Moon. Because the Full Moon is so bright, it’s difficult to observe deep-sky objects during this phase. But at the same time, the Moon makes an excellent target for beginning and experienced observers alike.

Monday, March 1
  Mars opens the month of March a mere 3° due south of M45, better known as the Pleiades. This sparkling open star cluster is easy to spot with the naked eye in the constellation Taurus (even with a nearly full moon) already relatively high in the southwest by the time full darkness falls.
APOD20191206.jpg
On March 30, 2019, Mars approached within 3.3° of the Pleiades star cluster in Taurus the Bull. A thin layer of clouds diffused the light from the Red Planet, producing the halo.

Tuesday, March 2
  The Moon reaches perigee — the closest point to Earth in its slightly elliptical orbit — at 9:18 A.M. PST. At that time, it will sit 227,063 miles (365,422 kilometers) away.

Thursday, March 4
  Asteroid 4 Vesta is at opposition today at 1 P.M. EST. You can find it in the constellation Leo tonight — the main-belt asteroid is now one of the top 10 brightest lights in the Lion’s hindquarters.
  Vesta, as its number indicates, was the fourth body discovered in the asteroid belt. At roughly 300 miles (480 km) across, it’s half the size of dwarf planet 1 Ceres.

The Big News
 Of course the Big news is currently the successful touchdown of the Perseverance Rover in Jezero crater on Mars. The landing was a spectacular success and was captured in the parachute phase by the Mars Reconnaissance Orbiter.

Asteroid in March. https://www.space.com/potentially-hazardous-asteroid-whizzes-near-earth-2001-fo32
 The space rock, officially called 231937 (2001 FO32), is about 0.5 to 1 mile (0.8 to 1.7 kilometers) in diameter and will come within 1.25 million miles (2 million kilometers) of Earth at 11:03 a.m. EST (1603 GMT) on March 21 — close enough and large enough to be classified as "potentially hazardous," a it whizzes by at almost 77,000 mph (124,000 km/h).

20
    Hi Tim:

    During fall 2019 I designed and built a new tube assembly for my 10 inch Newtonian optics.  It has some odd but useful features I'd like to share with other AU members who build telescopes. 
     
    Objectives of the design were as follows:
     
    1) Reduce weight and bulk of tube assembly & parts
    2) Make set-up assembly quick & simple in the dark
    3) Reduce tube currents and speed up cooling.
     
    The present configuration is the result of some trial & error.  Instead of a closed tube or open truss design it uses a rigid single-strut optical spar to hold the secondary and eyepiece assembly.   One bolt attaches the spar to the mirror box/altitude bearing assembly.  An adjustable counterweight makes use of a kid's lunch bag. The mirror box closes up to prevent condensation for immediate storage indoors after use on cold nights.  The tube works with a conventional Dob base which can ride on a commercial equatorial platform.  The focuser is a commercial 1.25"/ 2" inch 2 speed Crayford.
     
    Stray light is blocked simply by a removable baffle inserted into the focuser opposite to the eyepiece or camera.
     
    I use this scope with a ZWO CMOS camera operated and powered by a laptop computer.  This takes video clips, which I can stack using Registax, or still photos.
     
    I built this telescope using only hand tools (hacksaw and files) and a drill press. 
     
    Recently I took photos of this equipment set up in my back yard.  One photo is attached; showing the setup in use with the ZWO camera.  I have others showing more details and a stacked lunar image if there are questions.  I'm limited sending pictures with large megabyte contents.
     
    You're welcome to share this email and the photo with other AU members.
     
    Best wishes,
     
    Gail




I want to thank all you out there that are sharing your designs, builds , mirror results , images and everything in between. It is a true pleasure for me to send them along to you all and share. Thanks folks!


Stay safe everybody!!
Tim Crawford
Workshop Notes
Sent from my iPad

21
CCD or DSLR Images / Dick Beam 6 pages on his imaging
« on: February 27, 2021, 03:25:49 PM »
Download attached file for complete document with images.  Only the words from pdf file here:

I began my modern day quest in astrophotography about 3 years ago. I decided to buy
a Canon 6D, mkii, full-frame camera to shoot the heavens with. My style is such that I
like lots of stars and I like the variety of colors they have, albeit I like to have their
images small, with tight halos.
I had started out using DSS for pre-processing and Photoshop for processing and just
couldn’t make Photoshop work. I could never get any color in the stars with Photoshop,
nor could I get the color right; I guess I’m just too stupid for it. Dumb people like me
need a method or, if you’re a cook, a recipe and I just couldn’t find one that worked. I
mean no offence to any Photoshop people out there and I’ve seen very good work done
using Photoshop.
I kept looking for solutions and then I found all these pictures with star color, in fact color
galore. These images were done by processing them with software specifically
designed for deep sky astrophotography and one of these, Pixinsight, was the most
affordable solution for me so I went with it and I’ve never looked back since. Pixinsight
gave dumb people like me a method that I can work with.
DSS is another story and I continue to use it to this day as I think it’s a very fine
program and sometimes it works better for dumb people too, since the interface is
relatively straight forward. I used DSS to sample NEOWISE data over Pixinsight
because I couldn’t get a good master out of it; I guided on the comet head, incidentally,
because it was so star-like.
I knew going into using Pixinsight I had a severe learning curve ahead of me but a
method is a method so I decided to stick it out. It’s not like Pixinsight has a manual,
although they have some excellent mouse-over tool-tips so I got a book, called Inside
Pixinsight, by Warren A. Keller; my edition has a date of 2016 but I know there is a later
version so get that one if you’re interested.
So now I’ve got my method. The method always works but there’s always little things
that are different about every image so it’s not just cookie-cutter; you have to put some
thought into it or it wouldn’t be any fun.
If I look at the grand perspective of everything, what would be the hardest part about
Deep Sky Imaging? By far and away it’s the imaging: I’ve got to wait for the lunar cycle
to be right; the weather has to be good; I could be guiding in a troublesome spot for the
mount; something could go wrong during the shoot; I can be pretty stupid. Look, if
you’ve got the desire to go out in the cold, with the wind blowing, wait around until the
sky clears, get all setup just when the clouds arrive, repeat for several days, your well
on your way to being a stupid deep sky photographer like myself. All the advances in
technology, the software hurdles, all that stuff is chump-change compared to imaging.
I currently focus every 30 minutes and keep everything positioned very closely by using
a combination of techniques for dumb people. Once I get on target I record the RA and
DEC, draw cross-hairs on the PHD2 window with a dry ink marker using an overlay, and
take a screen shot of PHD2 in case I get way off somehow.
The first shot I’m going to show you is of the Trifid and Lagoon Nebula region shot with
a Redcat51 over 4 nights, and it’s full-frame, without a crop, giving testimony to my
dumb-people positioning technique. Also, the Redcat is a Petzval so it’s very similar to
Gary’s NP127 but it has a 250mm focal-length instead of 660mm. Notice how flat the
field is on the edges, a characteristic of having a married field-flattener to the optics. All
Petzvals are 4 element scopes and Gary’s 4th element is a doublet.
The next image is an image of one direction I want to go with Gary’s scope; I want to do
mosaicing and this image is my first crack at it. It’s only a 2 panel mosaic of M31 but it
employs a technique known as range compression, which I’ll go into later. The
mosaicing was done with the before mentioned source, Inside Pixinsight, and it was
just another easy method to follow so I’d say don’t sweat it; you need to have at least
20% overlap to do the merging and I think I’ve got about 30% here. The imaging was
done with a 10” Astrograph at f/3.9 over 8 nights. As you can see, the number of nights
just to shoot a couple of panels with range compression is a lot of a lunar cycle. In order to go over lunar cycles, I’m going to need a very staple, unchangeable setup – an
observatory, which is where the NP127 is going.
Sometimes targets have such a range in brightness that if you use a normal exposure
on it, it burns into the image and that part of the image can’t be stretched without some
distortion; such is the case on targets like M31 and M42. In order to do range
compression one needs to do so in processing, which won’t work if you’re already burnt
in, or by taking data with exposures that have decreasing amounts. If the exposure
technique is used, the exposures are blended together in Pixinsight by a process called
HDRComposition. The HDR in the process name stands for High Dynamic Range, a
process that adds the exposures together and re-normalizes them to intensity values
between 0 to 1 – a normal intensity range; the net effect is to bring down the brightness
of the brightest parts, while still allowing fainter parts to get more exposure. Stars will
always become smaller with such a technique because they are bright objects that will
have their brightness lowered, including their halo. This process is not going to yield an
image that’s like a normal image without range compression and I’m still learning and
making some changes as a result of what I now know.
M42 uses range compression similar to M31. I shoot at ISO 800 with the following
exposure sequence for range compression on the 10” Astrograph: 6 minutes, 3 minutes,
1 minute, and 30 seconds. M42 was shoot over 6 nights.
The technique works well on M13 too as you can see. Globular clusters have the
problem that the central stars can’t be resolved because the nucleus becomes a big
blob so this technique works very well with the same exposure plan as mention
previously.
Range compression works on comets and I used it when imaging NEOWISE. These
are 10 second, 20 second and 1 minute exposures in an HDRComposition. The
imaging was done on July 18, 2020. I had some atmospheric and light pollution in this
shot as it was low on the horizon. I had to quit when the scope’s FOV ran into the
fence.

22
January 25, 2021 SBAU radio hour on KZSB radio 1290AM.
Hosted by Baron Ron Herron (SBAU VP) with President JerryW, Outreach ChuckMcP, and Weebguy TomT.
Agenda suggested by JerryW is below, but download and play the attached MP3 audio file to listen to the actual program.

On 1/23/2021 11:30 PM, Jerry wrote:
>> Radio show of January 25, 2021

> Image.png "When you think about how huge the earth is, and how the earth is just a tiny ball orbiting the sun, which in turn 8is a minscule spec in the universe....it's pretty easy to rationalize eating an entire pie!
>
> This week, while the moon is bright
>    The Red Planet is easy to spot tonight from its perch high in Aries to the south after dark. With a large telescope or video capture capabilities, you may be able to make out features on its 8"-wide disk. The dark Syrtis Major and the large, circular Hellas basin feature centrally on the martian disk around 9 P.M. EST. Keep revisiting the Red Planet as the week progresses — the Moon will remain bright but peel away from the region, offering slightly better contrast with the dark background sky.
>    Just 2° southwest of Mars is the ice giant Uranus. At nearly magnitude 6 and with that bright Moon nearby — just over the border in Taurus — you’ll need at least binoculars to make it out. Look for a grayish “flat” star about half the size of Mars; of course, Uranus is physically much larger, but it sits nearly 20 times farther from Earth than the Red Planet, diminishing its size. Again, revisit this region in the coming days, but know that Uranus will remain a bit harder to find until the Moon’s light is no longer an issue.
>
> Looking at asteroids
> Vesta.jpg
> The large asteroid Vesta was one of two worlds the Dawn spacecraft visited. Dawn took this natural-color image of the rocky asteroid in July 2011.
> NASA/JPL/MPS/DLR/IDA/Björn Jónsson
>    Asteroid 4 Vesta, the second-most massive object in the main asteroid belt, currently shines at magnitude 6.8 in the hindquarters of Leo the Lion. It rises around 9 P.M., but wait an hour or two for the region to climb away from the more turbulent air near the horizon. By 10 or 11 P.M., pull out your binoculars to find Vesta just over 4° southwest of Denebola, which marks the tip of the Lion’s tail.
>    Asteroid 14 Irene is near opposition, rising in Cancer the Crab as the Sun sets, so any time after darkness falls is perfect to seek out the small world. You’ll find it glowing at magnitude 9.4 (a perfect binocular object) less that 2° due west of Iota (ι) Cancri, a fourth-magnitude star in the northern part of the constellation.
>
> Monday, January 25
>    Roughly two hours before sunrise, the Moon has finally set and Gemini the Twins are standing upright on the western horizon. The Twins’ heads, Castor (which appears on the right) and Pollux (left), shine brightly about 20° high.
>    They’re roughly the same magnitude (Pollux is a few tenths of a magnitude brighter) but through binoculars or a telescope, you may notice they’re slightly different colors: Castor appears blue-white, while Pollux is a bit more orange-hued. That’s because Castor is a hot type A star, while Pollux is a type K star and slightly cooler than the Sun.
>    But Castor has another advantage over Pollux: sheer numbers. A small telescope will reveal that Castor appears to be not one, but two stars about 4" apart. Called Castor A and B, both are type A stars. However, the Castor family is larger, still — Castor C, which is visible about 70" from A, is a cooler, dimmer type M star orbiting A and B together.
>
> Tuesday, January 26
>    Tonight, let’s visit Canis Major, which has cleared the horizon by two hours after sunset. Wait a little longer, and it will rise even higher in the sky.
    Again, the bright Moon is nearby, but tonight we’re seeking out a bright open cluster, NGC 2362, also called the Tau Canis Majoris Cluster after its brightest star: Fourth-magnitude Tau (τ) Canis Majoris. This star dominates the cluster’s light; you’ll need to train binoculars or a small scope on the region to see any of its neighbors. Look about 2.8° east-northeast of Wezen (Delta [δ] Canis Majoris), which marks the top of the Big Dog’s hindquarters, to find the cluster. It covers roughly 8' of sky, although some stars may be hard to spot with the Moon’s brighter background light. (So keep this target in mind and plan to return once the Moon’s phase has progressed.)
>    Tau itself is sometimes called the Mexican Jumping Star, possibly because it always remains relatively low in the sky. That, coupled with its relative brightness, makes it particularly susceptible to scintillation, which occurs when starlight is viewed through Earth’s turbulent atmosphere. This can cause a star to change apparent brightness and even color quite rapidly, sometimes looking as if you’re viewing it through a kaleidoscope. Sirius, the Dog Star, is also subject to this effect when it’s low on the horizon.
>
> Wednesday, January 27
>    With a nearly Full Moon in Cancer tonight, only bright stars are easily visible. After sunset, test your eyesight in Taurus the Bull, who hosts the famous Pleiades star cluster, also cataloged as M45. Most observers can see six or seven stars with the unaided eye, and that might be the most you’ll see tonight. But come back in several days on a darker night and you may see as many as 11 stars without optical aid, depending on the quality of your eyesight.
>    The Pleiades is a young open cluster of stars estimated at just a few tens of millions of years in age. Look to their southeast and you’ll find another open cluster of stars making the “v” of the Bull’s face: the Hyades, one of the closest open star clusters to Earth. Among them shines bright Aldebaran, the eye of the Bull, although this star is not actually part of the cluster. It’s also moving in a different direction on the sky than the cluster, meaning Taurus’ v-shaped visage will eventually start to deform over the next several tens of thousands of years.
>    Keep following a line drawn between the Pleiades and Hyades, and eventually you’ll reach Betelgeuse, the famous red giant star marking the shoulder of Orion the Hunter. This star became recently famous as it underwent a strange dimming event that astronomers attribute to a “stellar sneeze,” in which the star blew out a cool cloud of dust, temporarily blocking some of its light. It’s now back to its original brightness.
>
> Thursday, January 28
> Full Moon occurs at 11:16 A.M. PST; the traditional name for the January Full Moon is the Wolf Moon.
>    During Full Moon, our satellite rises just as the Sun is sinking below the horizon and remains visible all night. Aside from bright stars and planets, the Moon is likely the only thing you’ll be able to observe, so let’s zoom in on some of the features visible during this phase.
>    While the entire nearside of the Moon is on display at this time, it’s also directly illuminated by the Sun, which can wash out certain details. Some of the best spots to focus on during Full Moon include the craters Copernicus and its neighbor Kepler. Copernicus is located in Oceanus Procellarum on the left side of the Moon (when viewed unaided); Kepler is a bit farther to Copernicus’ lower left.
>    The huge crater Tycho is also hard to miss, dominating in the southern region of the Moon with long, bright streaks stretching away from it. These streaks, which also appear around Copernicus and Kepler, are rays of ejecta — material that was thrown up from the surface of the Moon when these features were created, flying as far as 750 to 1,200 miles (1,200 to 1,900 kilometers) from their point of origin.
>    Following in the footsteps of its fellow gas giant earlier this week, Jupiter is in conjunction with the Sun at 6 P.M. PST. It, too, will be visible in the early morning by mid-February.
>
> Friday, January 29
>    Rising only 30 minutes before the Sun, Venus makes for a challenging morning target in the eastern sky. Still, it’s bright at magnitude –3.9, increasing your chances of spotting it. If you can catch it through binoculars or a telescope, you’ll see its disk is roughly 10" across and nearly full (97% lit). Do take care when following it in the brightening sky, however — set an alarm for several minutes before local sunrise and call an end to using any optical aid at that time. This will eliminate the chance of accidentally swinging your optics toward the Sun after it’s risen, which can cause severe and permanent eye damage.
>    Venus’ fellow inferior planet, Mercury, is stationary against the background stars at 9 P.M. EST this evening. Before today, it was tracking northeast; now it will make a U-turn and head southwest. Tonight, you can follow this speedy planet in the west for more than an hour after sunset.
>
> Perserverance Rover will land on February 18 in Jezero Crater
https://www.nasa.gov/feature/jpl/7-things-to-know-about-the-nasa-rover-about-to-land-on-mars
 1. Perseverance is searching for signs of ancient life.
>    While the surface of Mars is a frozen desert today, scientists have learned from previous NASA missions that the Red Planet once hosted running water and warmer environments at the surface that could have supported microbial life.
> 2. The rover is landing in a place with a high potential for finding these signs of past microbial life.
>    More than 3.5 billion years ago, a river there flowed into a body of water about the size of Lake Tahoe, depositing sediments in a fan shape known as a delta. The Perseverance science team believes this ancient river delta and lake deposits could have collected and preserved organic molecules and other potential signs of microbial life.
> 3. Perseverance is also collecting important data about Mars’ geology and climate.
>    Context is everything. Mars orbiters have been collecting images and data from Jezero Crater from about 200 miles (322 kilometers) above, but finding signs of ancient life on the surface requires much closer inspection. It requires a rover like Perseverance.
> 4. Perseverance is the first leg of a round trip to Mars.
>    Rather than pulverizing rock the way the drill on NASA’s Curiosity rover does, Perseverance’s drill will cut intact rock cores that are about the size of a piece of chalk and will place them in sample tubes that it will store until the rover reaches an appropriate drop-off location on Mars. The rover could also potentially deliver the samples to a lander that is part of the planned Mars sample return campaign by NASA and ESA (the European Space Agency).
> 5. Perseverance carries instruments and technology that will help pave the way for human missions to the Moon and Mars.
>    Among the future-looking technologies on this mission that will benefit human exploration is Terrain-Relative Navigation. As part of the spacecraft’s landing system, Terrain-Relative Navigation will enable the descending spacecraft to quickly and autonomously comprehend its location over the Martian surface and modify its trajectory.
>    Perseverance will also have more autonomy on the surface than any other rover, including self-driving smarts that will allow it to cover more ground in a day’s operation.
>    In addition, Perseverance carries a technology experiment called MOXIE (short for Mars Oxygen In-Situ Resource Utilization Experiment) that will produce oxygen from Mars’ carbon dioxide atmosphere, for fuel or breathing.
>    Two other instruments will help engineers design systems for future human explorers to land and survive on Mars: The MEDLI2 (Mars Entry, Descent, and Landing Instrumentation 2) package is a next-generation version of what flew on the Mars Science Laboratory mission that delivered the Curiosity rover, while the MEDA (Mars Environmental Dynamics Analyzer) instrument suite provides information about weather, climate, and surface ultraviolet radiation and dust.
>    Perseverance is also giving a ride to the Ingenuity Mars Helicopter. A technology experiment separate from the rover’s science mission.
> 6. The Perseverance rover embodies the NASA – and the scientific – spirit of overcoming challenges.
>    Getting the spacecraft to the launch pad during a pandemic, searching for signs of ancient life, collecting samples, and proving new technologies are no easy feats. Nor is a soft touchdown on Mars: Only about 50% of Martian landing attempts, by any space agency, have been successful.
> 7. You will get to ride along.
>    The Mars 2020 Perseverance mission carries more cameras than any interplanetary mission in history, with 19 cameras on the rover itself and four on other parts of the spacecraft involved in entry, descent, and landing. As with previous Mars missions, the Mars 2020 Perseverance mission plans to make raw and processed images available on the mission’s website.
>
> The SBAU Tuesday Telescope Workshop is continuing with a growing attendance. To date participants have included: Tim Crawford, Chuck McPartlan, Gary Peterson, Mike Chibnik, Bob Grueneberg, Henk Aling, Joe Doyle, Robert Richard, Chris Ulivo, Farshad Barman, Jerry Wilson and hosted by our webmaster Tom Totton

23
Our VP and DJ BaRonH had TomT on for 15min to fill in for LadyKZSB at 830am. 
Download and play the attached MP3 audio file to listen in.

24
Download the attached MP3 audio file to listen to the Santa Barbara Astronomical Unit radio program hosted by the Baron Ron Herron on KZSB radio 1290AM

On 1/9/2021 9:42 PM, Jerry wrote:

> Radio Show Of Jan 11, 2021

> This Week
>    Although the universe is vast, galaxies often meet and interact. Such is the case with Bode’s Galaxy (M81) and the Cigar Galaxy (M82), two nearby spirals located about 10° northwest of Dubhe, Ursa Major’s magnitude 1.8 alpha star. The pair is visible in a small scope, whose low power can capture both in a single field of view — they sit roughly 35' apart. Higher power (or larger apertures) will reveal more detail in each, particularly in M81, whose spiral arms become visible under dark skies and greater magnification. The Cigar Galaxy, which gains its name from its long, skinny appearance, is tilted sideways with respect to Earth, meaning its dusty disk is visible edge-on, hiding its spiral arms.
>    After dark, Ursa Major is already climbing higher in the northern sky, with the Big Dipper oriented so the end of its handle touches the horizon. The Great Bear will continue her upward climb as the night progresses, eventually turning onto her back into the early morning as the stars near the North Pole rotate around it.

> Monday, January 11
>    Mercury passes 1.5° south of Jupiter at 3 A.M. PST. The pair is well below the horizon, invisible to observers.
>    Step outside early this morning before sunrise to spot the Moon and Venus sharing the sky in Sagittarius. Our Moon is a delicate crescent just over 3 percent lit, while Venus, less than 4° to its east, is 95 percent lit when viewed through a telescope. The planet is a bright magnitude –4, making it an easy-to-spot morning star.
>    Look about 23° west of Venus and you’ll find not Mars, but its doppelgänger: Antares, the red heart of Scorpius the Scorpion. This star earned its name because its brightness and color so closely match those of the Red Planet. But Mars is visible in the evenings this month; we’ll visit it later this week.
>    The Moon passes 1.5° south of Venus at 12 A.M. PST By tomorrow it will sit east of the planet, and Venus will rise well before our satellite appears in the sky.

> Tuesday, January 12
>    Today marks the end of the Quadrantid meteor shower, which peaked January 3. However, ambitious observers with dark skies may still be able to catch the shower’s last few stragglers. The Quadrantids’ radiant, located in the constellation Boötes, is high in the morning sky just an hour or two before sunrise. At its peak, the shower produced more than 100 meteors per hour, so some additional meteors above the random background level of seven or so per hour are still likely.
>    While you’re up this morning, look again for Venus, now preceding the Moon in the sky. In fact, our young satellite rises shortly before the Sun, by which time Venus is already 10° high. See how long you can follow it in the morning twilight, but avoid using optical aid of any kind after the Sun has risen to prevent accidentally damaging your vision.

> Wednesday, January 13
>    New Moon occurs at 9:00 A.M. PST. Our satellite less than a day old by sunset, but if you have a clear view of the southwestern horizon, it’s worth trying to see it. (Keep in mind, however, that this is a very difficult observation, and unlikely to bear fruit unless conditions are perfect.)
>    By sunset, our Moon is a less-than-1-percent-lit crescent. Search for it 20 to 25 minutes after sunset, when it will be just 1° above the horizon. Mercury, Jupiter, and Saturn are nearby — Mercury is just 6.5° northeast of our satellite, and the innermost planet is now located to the upper right of Jupiter, nearly 3.5° to Mercury’s lower right. Saturn is another 2.5° west of Jupiter, to the gas giant’s lower right. The three form a roughly straight line. Mercury will continue to pull away from the larger planets over the next several days, as the slowly waxing Moon does the same.

> Thursday, January 14
>    The Moon passes 2° south of Mercury at midnight PST; both are below the horizon at that time. Pluto is in conjunction with the Sun at 6. A.M. PST.
>    Also at 6 A.M. PST, Uranus is stationary against the background stars. The penultimate planet in our solar system is located in Aries the Ram, visible after sunset. You can easily pick out its magnitude 5.8 glow with binoculars or a small scope. Its 4"-wide disk will likely appear as a “flat” gray star.
>    Just 3.3° west of the ice giant is a much brighter planet: Mars, also making its way through Aries, shines at magnitude 0.1. Now 9" across, Mars is moving away from Earth along its orbit outside our own. Over the course of January, it will remain in Aries but shrink another 1" and dim a few tenths of a magnitude. Nonetheless, it remains an excellent evening object this month, readily visible in small and
>    If you return to this region of the sky night after night, you’ll see the Red Planet move noticeably northeast each night, passing 1.7° north of Uranus on the 21st. After tonight, Uranus will also begin inching northeast — but because it is much more distant, it appears to move much more slowly across the sky. The ice giant will remain within 4' of its current position all month, even as Mars flies quickly past.

> Friday, January 15
>    The strangely metallic asteroid 16 Psyche is located near Aldebaran, the red giant eye of Taurus the Bull, all month. It’s already well above the horizon at sunset. As soon as darkness falls, pull out your telescope and look 1.5° north of the bright star to find Psyche. Depending on your location, a 4-inch scope may be enough to spot it in a dark sky. Those in the suburbs might want a 6-incher or larger.
>    To positively identify the asteroid, you’ll want to return to this region again and again, noting which point of light has moved. Psyche travels about 6' per day (24 hours), so coming back day after day will show the most motion. The asteroid is currently moving northwest against the background stars. Around the 23rd, it will reverse course, starting to make its way northeast instead.
>    If you’re observing without a telescope, there’s still plenty to enjoy in the sky tonight. Once you’ve located Aldebaran, just slide your gaze about 14° northwest to spot the sparkling Pleiades star cluster. How many of its brightest stars can you count by eye, and can you make out its tiny “little dipper” shape? (Despite its shape, the Pleiades are not the Little Dipper. You’ll find that in the north, stretching outward from our pole star, Polaris.)

> Fun fact:
>    Asteroids can have rings too. Chariklo orbits between Saturn and Uranus and has two icy rings. Discovered by occultation observation.

> Drive by Star Shot
>    Every 50,000 years or so, a nomadic star passes near our solar system. Most brush by without incident. But, every once in a while, one comes so close that it gains a prominent place in Earth’s night sky, as well as knocks distant comets loose from their orbits.
>    The most famous of these stellar interlopers is called Scholz’s Star. This small binary star system was discovered in 2013. Its orbital path indicated that, about 70,000 years ago, it passed through the Oort Cloud, the extended sphere of icy bodies that surrounds the fringes of our solar system. Some astronomers even think Scholz’s Star could have sent some of these objectstumbling into the inner solar system when it passed.
>    However, Scholz’s Star is relatively small and rapidly moving, which should have minimized its effect on the solar system. But in recent years, scientists have been finding that these kinds of encounters happen far more often than once expected. Scholz’s Star wasn’t the first flyby, and it won’t be the last. In fact, we’re on track for a much more dramatic close encounter in the not-too-distant future.
>    “Scholz’s Star probably didn’t have a huge impact, but there should be many more stars that have passed through that are more massive,” astronomer Eric Mamajek of NASA’s Jet Propulsion Laboratory, whose 2015 paper in Astrophysical Journal Letters put Scholz’s Star on the map, tell Astronomy.
>    Around Christmas 2013, Mamajek was visiting a friend and fellow astronomer, Valentin Ivanov, at the offices of the European Southern Observatory in Santiago, Chile. While the two chatted, Ivanov was looking at recent observations of a star cataloged as WISE J072003.20–084651.2.
>    The star caught Mamajek’s interest because it was just about 20 light-years away, but astronomers hadn’t noticed it thanks to its dim nature and tiny apparent movement (or proper motion) across our night sky.
>    To him, those two things were a clue. Since it didn’t appear to be moving much side to side, the star was likely moving toward us or away from us at a breathtaking pace. As the astronomers continued talking, Ivanov measured the star’s radial velocity to learn how quickly it was moving toward or away from our Sun. Soon, they had their answer.
>    “Within five or 10 minutes, we had the initial results that this thing came within a parsec [3.26 light-years] of the Sun,” Mamajek says. “It was screaming through the solar neighborhood.”
>    The two astronomers and their colleagues would eventually show that it passed even closer than that. In fact, it passed closer to our Sun than any other known star. This status prompted them to name the cosmic trespasser after its initial discoverer, an astronomer named Ralf-Dieter Scholz, who’s devoted significant time to finding nearby stars.
>    Mamajek has since moved on from studying Scholz’s Star. But in the meantime, other astronomers have also taken up the work. And, thanks to a European Space Agency satellite called Gaia, which is built to map the precise locations and movements of over a billion stars, we now know about other close encounters.
>    In 2018, a team of researchers led by Coryn Bailer-Jones of the Max Planck Institute for Astronomy in Germany, used Gaia data to plot our Sun’s future meet-ups with other stars. They discovered nearly 700 stars that will pass within 15 light-years of our solar system over just the next 15 million years. However, the vast majority of close encounters have yet to be discovered, the team suggests. But they suspect roughly 20 stars should pass within just a couple light-years of us every million years.
>    However, “space is big,” Mamajek points out. “Statistically, most of those stars would pass the outer edge of our solar system.” That means encounters like the one with Scholz’s Star are common, but only a few are close enough to actually dislodge a significant number of comets,
>    Nonetheless, a few stars should still come surprisingly close. And if a large, slow-moving star did pass through the edge of the Oort Cloud, it could really shake up the solar system.
> starsnextdoor.jpg
> Many nearby stars will pass close to the Oort Cloud, but only one will move through it. In about 1.35 million years, Gliese 710 likely will gravitationally perturb millions of comets, sending a sizable number on a potential collision course with Earth.
> Astronomy: Roen Kelly
>    A massive star steamrolling through the outer solar system is exactly what Gaia data show will happen less than 1.4 million years from now, according to a 2016 study. A star called Gliese 710 will pass within 10,000 astronomical units — 1 AU is equal to the average Earth-Sun distance of 93 million miles. That’s well within the outer edge of the Oort Cloud.
>    At half the mass of the Sun, Gliese 710 is much larger than Scholz’s Star, which is just 15 percent the mass of the Sun. This means Gliese 710’s hulking gravity could potentially wreak havoc on the orbits of icy bodies in the Oort Cloud. And while Scholz’s Star was so tiny it would have been barely visible in the night sky — if at all — Gliese 710 is larger than our current closest neighbor, Proxima Centauri. So when Gliese 710 reaches its closest point to Earth, it will burn as a brilliant orange orb that will outshine every other star in our night sky.
>    This event could be “the strongest disrupting encounter in the future and history of the solar system,” the authors wrote in their paper, published in the journal Astronomy & Astrophysics.
>    Fortunately, the inner solar system is a relatively tiny target, and even if Gliese 710 does send comets flying our way, it would take millions of additional years for these icy bodies to reach us. That should give any surviving future humans plenty of time to take action.

> Was the Sun Half of a Binary?
>    Scientist believe that surrounding the generally flat solar system is a spherical shell comprised of more than a trillion icy objects more than a mile wide. This is the Oort cloud, and it's likely the source of our solar system's long-term comets — objects that take 200 years or more to orbit the Sun. Inside that shell and surrounding the planets is the Kuiper Belt, a flat disk of scattered objects considered the source of shorter-term comets.
>    Long-term comets come at us from all directions and astronomers at first suspected their origins to be random. However, it turns out their likely trajectories lead back to a shared aphelion between 2,000 astronomical units (AU) from the Sun to about 100,000 AU, with their different points of origin revealing the shell shape of the Oort cloud along that common aphelion. (An astronomical unit is the distance from the Sun to the Earth.)
>    No object in the Oort cloud has been directly observed, though Voyager 1 and 2, New Horizons, and Pioneer 10 and 11 are all en route. (The cloud is so far away that all five of the craft will be dead by the time they get there.) To derive a clearer view of the Oort cloud absent actually imagery, scientists utilize computer models based on planetary orbits, solar-system formation simulations, and comet trajectories.
>    It's generally assumed that the Oort cloud is comprised of debris from the formation of the solar system and neighboring systems, stuff from other systems that we somehow captured. However, says paper co-author Amir Siraj of Harvard, "previous models have had difficulty producing the expected ratio between scattered disk objects and outer Oort cloud objects." As an answer to that, he says, "the binary capture model offers significant improvement and refinement, which is seemingly obvious in retrospect: most sun-like stars are born with binary companions."
>    “Binary systems are far more efficient at capturing objects than are single stars," co-author Ari Loeb, also of Harvard, explains. "If the Oort cloud formed as [indirectly] observed, it would imply that the sun did in fact have a companion of similar mass that was lost before the sun left its birth cluster."
>    Working out the source of the objects in the Oort cloud is more than just an interesting astronomical riddle, says Siraj. "Objects in the outer Oort Cloud may have played important roles in Earth's history, such as possibly delivering water to Earth and causing the extinction of the dinosaurs. Understanding their origins is important."
>    The gravitational pull resulting from a binary companion to the Sun may also help explain another intriguing phenomenon: the warping of orbital paths either by something big beyond Pluto — a Planet 9, perhaps — or smaller trans-Neptunian objects closer in, at the outer edges of the Kuiper Belt.
>    “The puzzle is not only regarding the Oort clouds, but also extreme trans-Neptunian objects, like the potential Planet Nine," Loeb says. "It is unclear where they came from, and our new model predicts that there should be more objects with a similar orbital orientation to [a] Planet Nine."
>    The authors are looking forward to the upcoming Vera C. Rubin Observatory (VRO) , a Large Synoptic Survey Telescope expected to capture its first light from the cosmos in 2021. It's expected that the VRO will definitively confirm or dismiss the existence of Planet 9. Siraj says, "If the VRO verifies the existence of Planet Nine, and a captured origin, and also finds a population of similarly captured dwarf planets, then the binary model will be favored over the lone stellar history that has been long-assumed."
>    Lord and Siraj consider it unsurprising that we see no clear sign of the Sun's former companion at this point. Says Loeb, "Passing stars in the birth cluster would have removed the companion from the sun through their gravitational influence. He adds that, "Before the loss of the binary, however, the solar system already would have captured its outer envelope of objects, namely the Oort cloud and the Planet Nine population."

25
Download attached file about attaching a camera to your Dobsonian Telescope for quick astrophotography.
The wording is here, but the attachment has the images also.

Make Your Dobson Newtonian Go Virtual
By Jürgen Hilmer - January 2021
Many are Zooming to share during the current crisis. Turn your Dobson Newtonian telescope
into a zooming scope. Email and share your images with others. The Dobson Newt with its
rocker box mount came around many years ago. To get your Newt to shoot photos of bright
night sky objects and to send them to others (like the Moon and some planets) all you need is a
2X Barlow. If fainter objects are the target, an equatorial platform placed under the Dobson
Newt rocker box mount can be of help.
The 2X Barlow like a Celestron Ultima, unscrewed, works. Install the optical chrome barrel into
a camera (Canon T4i) body cap. Since the optics are closer now to the camera sensor, the
Barlow becomes a 3X. The above process makes it possible to focus on night sky objects
without rebuilding the inside of the telescope tube. No getting the secondary mirror closer to the
primary mirror, or cutting a new hole for the focuser. A scope like a 1500mm f4.5 with a 330mm
(13”) diameter mirror is an example.
To photograph the fainter objects, which need longer exposure times, an equatorial platform is
needed. This platform fits under the rocker box mount. It keeps the target object in the field of
view and on the camera sensor for about 30 minutes. After that, pulling on the platform resets it,
and it is good for another 30 minutes of tracking. The Osypowski equatorial platform and others
are on the used market; kits are sold, and many sites help in building your own.
In a previous article find some helpful information on more scopes, cameras, and sharing
images:  http://www.sbau.org/201219%20Jurgen_Article.pdf  "Share Images Your Telescope Sees With Others" by Jürgen Hilmer, December, 2020
Please refer to the following three sites for some of the best information.
1. The Barlow Lens:  https://britastro.org/node/15666
2. EQ Platform (Link in left panel of page):  http://www.reinervogel.net/index_e.html?/Artikel_e.html
3. Tom Osypowski Equatorial Platform:  http://www.equatorialplatforms.com/

To sit with and contemplate how huge 13.8 billion light years is, and how tiny Planck time is, and
now add a pinch of EPR Entanglement, and all this only known to us for the last 100 years. Ah,
how inspiring a Dobson Light Bucket can be!

26
Download the attached mp3 audio file to listen to the program.

On 12/26/2020 11:56 PM, Jerry wrote the following possible agenda for the SBAU radio hour:
>
> This Week
>    The Quadrantid meteor shower, which peaks the morning of January 3, has begun ramping up. Unfortunately, there’s a bright Moon in the sky between now and the shower’s peak; however, given its expected maximum rate of 120 meteors per hour, patient observers still stand a good chance of catching bright shower meteors as the peak approaches. This is particularly true as the Quadrantids often produce bright fireballs — meteors that briefly flare to magnitude –3 or brighter.
>    The shower’s radiant lies in another extinct constellation — Quadrans Muralis. Today, that sits in the constellation Boötes, home to the familiar bright star Arcturus. The region rises after midnight and stands highest in the eastern sky before dawn, so early mornings for the next several days will be the best time to hunt down shower meteors. This shower is associated with two parent bodies: Comet 96P/Machholz and the minor planet 2003 EH1. Its particles streak through the atmosphere at speeds of 26 miles (42 kilometers) per second — medium fast, as far as meteors go.
>
> Monday, December 28
>    A week after their Great Conjunction, Jupiter and Saturn are still sharing close quarters in the sky. They’re less than 1° apart, with magnitude –2 Jupiter just east of magnitude 0.6 Saturn.
>    Just like last week, you’ll want to start looking for them low in the southwest as soon as twilight begins to darken the sky because they’re both sinking fast. And just like last week, Ganymede is closing in for another transit across Jupiter’s disk — this one doesn’t start until about 7:30 P.M. PST, however, long after the planet has set for those in the continental U.S.
>    As the gas giants sink below the horizon, look west to see bright Altair in Aquila, now only about 15° high. From Altair, look north-northwest to spot Vega in Lyra; from Vega, gaze east-northeast to find Deneb in Cygnus. These three stars create the familiar Summer Triangle, which gains its name from its position high overhead on summer nights. Now that it’s winter, the Triangle will set earlier and earlier, until its three stars are below the horizon during the cold nighttime hours.
>
> Tuesday, December 29
>    Full Moon occurs at 7:28 P.M. PST tonight. Because our bright satellite washes out much of the sky with its glare, consider getting to know some of the terrain on Earth’s closest neighbor instead.
>    The face of the Moon we see from Earth has several dark splotches visible to the naked eye. These are its maria, or seas, although they were never filled with water. Instead, these dark regions are ancient lava flows. Some of the most easily recognizable are Mare Imbrium and Oceanus Procellarum in the lunar west (the Moon’s left side as you see it in the sky), and Mare Serenitatis, Mare Tranquillitatis, and Mare Fecunditatis in the lunar east (the Moon’s right side in the sky).
>    Near the bottom of the Moon is a large crater — Tycho — with long, bright rays of material stretching almost halfway up the face of our satellite. These are made of material thrown up during the impact that formed the crater, which traveled great distances in the Moon’s low gravity to ultimately sink down to the ground much farther away.
>
> Wednesday, December 30
>    With a Full Moon still lighting the sky, fainter objects remain hard to find. Instead, search out some of the brighter sky treasures, such as the V-shaped Coma Star Cluster (Melotte 111) in Coma Berenices, which appears above Virgo as they rise in the southeast this morning.
>    By 4 A.M., the cluster is more than 60° high. One of the easiest ways to find it is to first find Leo the Lion, then draw a line between his brightest star, Regulus, and Zosma, which marks the top of his hindquarters. Follow that line about the same distance off to the northwest and you’ll hit the Coma Star Cluster. This young, loose open cluster contains roughly 100 stars less than 300 light-years away. The members range in magnitude from 5 to 10, so while some are visible to the naked eye under dark conditions, your binoculars or telescope will bring out many more.
>
> Thursday, December 31
>    Tonight there’s a test for your eyes waiting in the sky. Shortly after dark, Ursa Major is starting to climb her way upward in the sky. By 9 or 10 P.M. local time, her long tail is fully on view; you may recognize this as the kinked handle of the Big Dipper. And right at that kink — the second star from the end — is your challenge. This is the naked-eye binary system Mizar and Alcor. Mizar is magnitude 2, while Alcor is much fainter at magnitude 4. The pair is separated by just 11.8', with Alcor floating slightly northeast of its brighter companion.
>    Many people are able to spot both stars under clear, calm conditions. If you’re having trouble, wait a little while to give the stars time to rise higher above the horizon (where the air can be more turbulent). What’s more, Mizar itself is a binary whose components can be split with a small telescope. Sitting 14" apart, this pair was discovered in 1650. And each of these stars is also a double, although they cannot be visually distinguished.
>
> Friday, January 1
>    Ring in the new year with Earth’s sister planet, Venus. It rises as a morning star more than an hour before the Sun this morning, but clings low to the southeastern horizon as dawn brightens the sky. The planet is now located 12° east of the famous star Antares, and 2.5° north-northwest of magnitude 3 Theta (θ) Ophiuchi.
>    Venus is currently on the far side of the Sun from our vantage point, located one and a half times the average Earth-Sun distance from our planet, but only a little over half that distance from the Sun. Its disk appears 94 percent lit and spans 11".
>    Scan northeast a bit and you’ll see some familiar sights — Vega and Deneb, two points of the Summer Triangle, are now rising in the predawn sky. Along with Altair, the Triangle’s third point, they will traverse the sky during daytime for the next few months, until our planet’s journey around the Sun brings us back to the summer season.
>
> Ryugu and Bennu.
>    The Hayabusa2 mission successfully collected a sample from a near-Earth asteroid and returned it to Earth -- as well as the first gas sample from deep space, according to the Japan Aerospace Exploration Agency, or JAXA.
>    The sample was dropped off on Earth by a capsule on December 6 in South Australia. Teams from JAXA were able to retrieve the capsule where it landed and conduct some preliminary tests of gas in the capsule before it was sent to Japan.
>    The Hayabusa2 probe accomplished its mission, collecting a sample from the near-Earth asteroid Ryugu and returning it to Earth, according to JAXA.
> The gas was the first step in helping the researchers to confirm that the spacecraft successfully collected a sample from Ryugu in 2019 when the spacecraft visited the asteroid.
>    Researchers confirmed that the gas originated from Ryugu because their analysis of the gas shows that it is different from the atmospheric composition on Earth. Two separate analyses, one in Australia on December 7 and another between December 10 to 11 at the Extraterrestrial Sample Curation Center on the JAXA Sagamihara Campus, helped the teams arrive at the same result.
>    The gas likely came from the collected material on the surface and beneath the surface of the asteroid itself. The researchers will continue opening the capsule containing the sample to understand more about the gas.
>    The team also confirmed that black sand grains are also inside the sample container, further confirmation that there is asteroid material inside the capsule.
>    By the end of 2021, JAXA will share tiny samples from Ryugu to six teams of scientists across the globe. Meanwhile, Hayabusa2 continues on its path after flying by Earth in early December to drop off the capsule and will visit more asteroids in the future.
>    Hayabusa2 launched on December 3, 2014, and arrived at the near-Earth asteroid Ryugu in June 2018. The spacecraft collected one sample from the asteroid's surface on February 22, 2019, then fired a copper "bullet" into the asteroid to create a 33-foot wide impact crater. A sample was collected from this crater on July 11, 2019.
> Then, Hayabusa2 departed the asteroid in November 2019 and journeyed back to Earth.
>    Altogether, the mission's scientists believes one gram of material was collected, but they can't be sure until they open it completely. “One gram may sound small, but for us, one gram is huge," said Masaki Fujimoto, deputy director general of the department of solar system sciences at JAXA, during an online briefing hosted by the Australian Science Media Centre. "It is enough to address our science questions."
>    The agency's first Hayabusa mission returned samples from the asteroid Itokawa to Earth in June 2010, but scientists said that due to failure of the spacecraft's sampling device, they were only able to retrieve micrograms of dust from the asteroid.
>    “Ryugu is linked to the process that made our planet habitable," Fujimoto said. "Earth was born dry; it didn't begin with water. We think distant bodies like Ryugu came to the inner part of solar system, hit Earth, delivered water and made it habitable. That's the fundamental question we're after and we need samples to solve that."
> Asteroids are like leftovers from the formation of our solar system, preserving information about the origins of planets as well as the vital elements that allow life to exist on Earth.
>    The NASA OSIRIS-REx mission recently collected a sample from another near-Earth asteroid, Bennu, that is similar in composition to Ryugu. In fact, based on early data from both missions, scientists working on both missions believe it's possible these two asteroids once belonged to the same larger parent body before it was broken apart by an impact.
> The Bennu sample will be returned to Earth by 2023.       
> Patrick Michel, director of research at the French National Centre for Scientific Research in Paris, is an investigator for both missions.
> "It is really important to realize that no two asteroids are the same," Michel told CNN in October. "Even if Bennu and Ryugu share some intriguing similarities and belong to the same category (primitive), they also have some very interesting differences. And these samples will occupy generations of researchers as a large amount will be kept for future generations that will benefit from the increase in technology and accuracy of the instruments used to analyze them."

27
Download attached mp3 audio file to listen.

On 12/12/2020 7:29 PM, Jerry wrote:>
> Radio show of December 14, 2020 possible agenda

Monday, December 14
>    New Moon occurs today at 8:17 A.M. PST — and with it comes the last total solar eclipse of the year, visible from Chile and Argentina.
>    The total path length of this eclipse is 9,239 miles (14,869 km), but only 5 percent of this path falls on land. Fortunately, that 5 percent is where the eclipse’s longest duration of 2 minutes 10 seconds occurs, near Sierra Colorada, Argentina, at 4:13 P.M. UT.
    Total solar eclipses occur when the Moon passes between Earth and the Sun, blocking our star from view and allowing us to see its tenuous outer atmosphere, the corona. But another condition must be met — the Moon must be the right distance away from Earth in its orbit to completely cover the Sun. Because the Moon’s orbit is slightly elliptical, if it is too far from Earth when it passes between us and our star, it doesn’t appear large enough to completely block the Sun. When this happens, we see an annular solar eclipse, during which an outer ring of the Sun’s surface remains visible.
>
> Tuesday, December 15
>    The constellation Perseus the Hero is high in the sky several hours after sunset. He’s home to the famous Double Cluster, comprising NGC 869 and NGC 884 (also called H and Chi [χ] Persei). From a dark location — and with no Moon, like tonight — you may be able to spot them with the naked eye. In fact, early observers first cataloged this pair around 130 B.C.
>    Start your search at Perseus’ alpha star, Mirfak, which glows at magnitude 1.8. Look north-northwest of Mirfak to find magnitude 2.9 Gamma (γ) Persei, then north-northwest again to find magnitude 3.8 Eta (η) Persei. The Double Cluster sits about 4° northwest of this star and will likely appear as one or two fuzzy patches to your unaided eye.
>    Binoculars or a telescope will bring out these open clusters’ myriad stars. Each contains several hundred young suns some few million to 10 million years old — extremely young by stellar standards.
>
> Wednesday, December 16
    Look southwest after sunset for a triple treat tonight: The thin crescent Moon lies less than 6° southwest of bright Jupiter and Saturn. Our satellite shares the constellation Sagittarius with the solar system’s largest planet, while Saturn stands just over the invisible border in Capricornus. Look first at the Moon to see if you can spot the earthshine effect — sunlight reflecting off Earth and illuminating the portion of the Moon still in shadow.
>    The Moon also provides a perfect tool for comparison. Tonight, the ringed planet (magnitude 0.6) is just 0.5° from Jupiter (magnitude –2) — that’s the width of the Full Moon in the sky. But they’re going to get even closer. On the night of the winter solstice next week, the pair will form a nearly indistinguishable “star” in the sky as they come within 0.1° of each other. In a low-power binocular or telescope field, you’ll be able to see both in a single view. This is a sight you won’t want to miss, so begin planning your observations now.
>    Later tonight, the Moon will pass 3° south of Jupiter at 8 P.M. PST. Our satellite will then pass 3° south of Saturn at midnight EST.
>
> Thursday, December 17
>    Bright Vega in Lyra is hard to miss in the evening sky, blazing in the northwest after sunset. Although this magnitude 0 luminary far outshines the other stars in its constellation, there are many more reasons to explore the rest of the Harp.
>    One is Sheliak (Beta [β] Lyrae), a multiple-star system that sits 6° south-southeast of Vega. Through binoculars or a small scope, you can easily resolve a magnitude 3.6 primary and a magnitude 6.7 secondary separated by 45". Furthermore, the brighter star, Beta A, is an eclipsing binary (think Algol in Perseus), swinging between magnitude 3.3 and 4.3 in a little less than 13 days as its companion passes in front of and behind it. At maximum, Beta is closest in brightness to nearby Gamma (γ) Lyrae, about 2° to its east. At minimum, it better matches Zeta (ζ) Lyrae, 4.5° north.
>    Zeta is also a multiple-star system, comprising as many as seven stars. Through binoculars, you can easily separate Zeta A and B — A is the brightest at magnitude 4.3, while B is a dimmer magnitude 5.6 and sits 44" away from its companion.
>
> Friday, December 18
>    Zoom in on the Moon today for a look at an interesting crater doublet: Messier and Messier A. You’ll find our satellite low in the south at sunset, but there are a few hours of darkness to observe before it sinks below the horizon around 9 P.M. local time.
>    Look with a telescope toward the Moon’s eastern limb, along its equator. There you’ll find the large crater Langrenus, with its distinctive central peaks. To the northwest of this crater is a small pair of impacts; the westernmost pockmark has a distinctive cometlike trail of debris spreading farther west. These are Messier and Messier A, named for the famous 18th-century comet hunter Charles Messier. The pair’s strange appearance is attributed to a single impact that struck the Moon at a low angle and essentially skipped once along the surface.
>    Bump your magnification up to 100x and you’ll see the Messier doublet is distinctly out of round when compared with its fellow craters. Come back over the next few nights for even better views of its one-way rays, as the changing Sun angle brings them into even better contrast.
>
>
> The Big Show is Coming Up
> The gas giant planets, Jupiter snd Saturn will be in conjunction (appear close together in the sky) on December 21, a week from today, but before our next radio show. But the are worth observing and imaging starting now for the next two weeks. The planets and their moons, the four Galilean moons of Jupiter and at least Titan with Saturn, will all fit in the same telescopic field of view of small telescopes and binoculars. The last time such a close conjunction was easily observable was in 1226. If you want to wait for their next very close conjunction, it will be on March 15, 2080, but only briefly visible in the predawn sky.
>    With the pandemic, the SBAU is not able to host any public viewing events. People who want to see the conjunction should find a spot with a clear horizon to the southwest. Sunset will be around 4:53 PM PST, and at that time Jupiter and Saturn will be visible in the southwest at an altitude of 22 degrees above the horizon, about twice the apparent width of a fist held at arm's length. They will set around 7 PM.
>
> Exo-Planet 9?
>    A planet in an unlikely orbit around a double star 336 light-years away may offer a clue to a mystery much closer to home: A hypothesized, distant body in our solar system dubbed "Planet Nine."
>    This is the first time that astronomers have been able to measure the motion of a massive Jupiter-like planet that is orbiting very far away from its host stars and visible debris disk. This disk is similar to our Kuiper Belt of small, icy bodies beyond Neptune. In our own solar system, the suspected Planet Nine would also lie far outside of the Kuiper Belt on a similarly strange orbit. Though the search for a Planet Nine continues, this exoplanet discovery is evidence that such oddball orbits are possible.
> "This system draws a potentially unique comparison with our solar system," explained the paper's lead author, Meiji Nguyen of the University of California, Berkeley. "It's very widely separated from its host stars on an eccentric and highly misaligned orbit, just like the prediction for Planet Nine. This begs the question of how these planets formed and evolved to end up in their current configuration."
>    The system where this gas giant resides is only 15 million years old. This suggests that our Planet Nine—if it does exist—could have formed very early on in the evolution of our 4.6-billion-year-old solar system.
>    The 11-Jupiter-mass exoplanet called HD 106906 b was discovered in 2013 with the Magellan Telescopes at the Las Campanas Observatory in the Atacama Desert of Chile. However, astronomers did not know anything about the planet's orbit. This required something only the Hubble Space Telescope could do: Collect very accurate measurements of the vagabond's motion over 14 years with extraordinary precision. The team used data from the Hubble archive that provided evidence for this motion.
>    The exoplanet resides extremely far from its host pair of bright, young stars—more than 730 times the distance of Earth from the Sun, or nearly 6.8 billion miles. This wide separation made it enormously challenging to determine the 15,000-year-long orbit in such a relatively short time span of Hubble observations. The planet is creeping very slowly along its orbit, given the weak gravitational pull of its very distant parent stars.
>
>    How did it get there?
>    So how did the exoplanet arrive at such a distant and strangely inclined orbit? The prevailing theory is that it formed much closer to its stars, about three times the distance that Earth is from the Sun. But drag within the system's gas disk caused the planet's orbit to decay, forcing it to migrate inward toward its stellar pair. The gravitational effects from the whirling twin stars then kicked it out onto an eccentric orbit that almost threw it out of the system and into the void of interstellar space. Then a passing star from outside the system stabilized the exoplanet's orbit and prevented it from leaving its home system.
>    Using precise distance and motion measurements from the European Space Agency's Gaia survey satellite, candidate passing stars were identified in 2019 by team members Robert De Rosa of the European Southern Observatory in Santiago, Chile, and Paul Kalas of the University of California.
>
>    A target for the Webb Telescope
>    Scientists using NASA's upcoming James Webb Space Telescope plan to get data on HD 106906 b to understand the planet in detail. "One question you could ask is: Does the planet have its own debris system around it? Does it capture material every time it goes close to the host stars? And you'd be able to measure that with the thermal infrared data from Webb," said De Rosa. "Also, in terms of helping to understand the orbit, I think Webb would be useful for helping to confirm our result."
>    Because Webb is sensitive to smaller, Saturn-mass planets, it may be able to detect other exoplanets that have been ejected from this and other inner planetary systems. "With Webb, we can start to look for planets that are both a little bit older and a little bit fainter," explained Nguyen. The unique sensitivity and imaging capabilities of Webb will open up new possibilities for detecting and studying these unconventional planets and systems.
>    The team's findings appear in the December 10, 2020, edition of The Astronomical Journal.
>
>
> Hubble Catches Rapid Fading Of A Disappearing Nebula   
>    Hubble has revealed the drastic fading of a nebula, capturing it going through unprecedented changes over a 20-year period. When it comes to objects of the cosmos, we’re more used to thinking of changes in terms of millions, if not billions, of years, not decades.
>    The nebula Hen 3-1357, better known as the Stingray nebula, was already an exciting discovery. Hailed as the youngest known planetary nebula in 1998 when Hubble first peeked inside its central star’s final stages of life, now it’s been caught doing something that even the Hubble team are calling “weird”.
>    Photographed by Hubble in 1996, the nebula’s bright blue tendrils and filaments of gas at its center meant it popped against its dark dramatic background, its wavy edges giving it its stingray moniker. Now archival data shows that by 2016, the nebula had dimmed and its wavy edges had almost disappeared.
>
>    “This is very, very dramatic, and very weird,” said Hubble member Martín A. Guerrero in a statement. “What we’re witnessing is a nebula’s evolution in real-time. In a span of years, we see variations in the nebula. We have not seen that before with the clarity we get with this view.”
>    The dimming is down to changes in the light emitted by the glowing hydrogen, nitrogen, and oxygen being emitted by the dying star at its center. According to researchers, the oxygen emission dropped by a factor of nearly 1,000 over the two decades.
>    “Changes in nebulae have been seen before, but what we have here are changes in the fundamental structure of the nebula,” said Bruce Balick, leader of the new research due to be published in The Astrophysical Journal. "In most studies, the nebula usually gets bigger. Here, it’s fundamentally changing its shape and getting fainter, and doing so on an unprecedented time scale. Moreover, to our surprise, it’s not growing any larger. Indeed, the once-bright inner elliptical ring seems to be shrinking as it fades.”
>    The culprit appears to be the Stingray nebula's central star, SAO 244567, which experienced a rapid rise in temperature, from less than 22,000°C (40,000°F) to 60,000°C (108,000°F), according to a 2016 study based on observations of the nebula between 1971 and 2002. After the star expanded, causing the temperature to drop, the star went through a cooling phase, emitting less ionizing radiation. Hubble effectively caught before and after shots.
>    Now that the star is cooling, it's likely returning to its early stage of stellar evolution that it was experiencing before its temperature jump. It's hard to know what's in store for this nebula with it being so young, but the researchers estimate that at its current rate of fading, it may be barely detectable in just two or three decades.
>    Serendipitously, Hubble was in the right place at the right time to capture the rapid changes which, in cosmic terms, occurred in just the blink of an eye.
> By Katy Evans  > 04 DEC 2020, 17:30

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Download the attached mp3 audio file to play.  46 minutes with the advertisements cropped out.  Sorry, between 15-18 minutes in, I mistakenly was playing a video from the Saturday, November 21, 2020 SpaceX launch and recovery of the Falcon 9 rocket, so voices from that are on top of the radio show.  But listen closely to this and you can hear the sonic boom that happened shortly after the rocket 1st stage touched down.   The breaking of the sound barrier was probably 10 miles up, so that would reach the ground about 50 seconds later, after the rocket had landed.  I will post that video at https://www.youtube.com/channel/UCU0r4RxzoyT_pwNcfN5aJsA/videos soon.

On 11/21/2020 11:04 PM, Jerry wrote this list of possible subjects to discuss:

>Monday, November 23
>    The Moon passes 5° south of Neptune at 4 A.M. PST, but both are below the horizon at the time. Instead, you can catch the pair after sunset, when they are just over 6° apart in the constellation Aquarius.
>    Neptune, whose dim magnitude 8 glow will require binoculars or a small scope, presents a bluish disk just 2" across. It currently sits less than 1° east of magnitude 4.2 Phi (φ) Aquarii. Neptune is now roughly 30 astronomical units from Earth, where 1 astronomical unit, or AU, is the average Earth-Sun distance, and a fraction of an AU is now doing this show. That means its light takes a little over four hours to reach us here on Earth. Neptune has been slowly sliding southwest against the background stars, but in just a few days it will reach its stationary point and about-face to begin tracking northeast.
>
>
> Tuesday, November 24
>    Starting an hour before sunrise, both Mercury and Venus should be easy to spot in the brightening sky. Mercury, just rising among the stars of Libra, is an easy magnitude –0.7. Venus is impossible to miss at magnitude –4. It’s sitting less than 2° from magnitude 4 Kappa (κ) Virginis and is now 10° due east of bright Spica.
>    Through a telescope, Mercury appears 90 percent illuminated and 5" across. It is just 0.5° from Nu (ν) Librae, whose dim, magnitude 5 glow will fade quickly as dawn approaches. Venus is a much larger 12" across, with a disk that’s 87 percent lit.
>    See how long you can follow the planets into the morning sky, but take care — stop using any optical equipment, including binoculars, at least several minutes before sunrise to avoid accidentally damaging your eyes.
>
>
> Wednesday, November 25
>    The Moon passes 5° south of Mars at 12 P.M. PST. By sunset, our satellite is just 5.2° from the Red Planet. Mars remains in Pisces the Fish, while the Moon is south-southwest of the planet, just over the border in Cetus the Whale.
>    Let full darkness fall, then swing your scope to Mars to observe its 15"-wide disk, which shines at magnitude –1.3. Around 8 P.M. EST, the bright spot of Olympus Mons is visible on the disk; it will rotate out of view over the next two hours or so. The dark swaths of first Mare Sirenum, and later Mare Cimmerium, are also visible south of Olympus Mons.
>    NASA’s Mars 2020 mission is now less than 100 days from its landing on Mars. Recently, mission scientists released audio recorded by the Perseverance rover’s microphones as it travels through deep space. The sound is generated by mechanical vibrations that the microphone’s equipment has turned into an electrical signal. The soft buzz comes from the rover’s heat rejection fluid pump, which maintains the equipment’s temperature even in frigid cold.
> Perseverance Rover's Interplanetary Sounds  https://soundcloud.com/nasa/perseverance-rover-sounds
>
>
> Thursday, November 26
>    The Moon reaches the farthest point from Earth in its orbit around our planet, called apogee, at 4:29 P.M. PST. At that time, our satellite will sit 252,211 miles (405,894 km) from Earth.
>    With our satellite visible all evening, it’s a great time to explore its pockmarked face. You’ll find the Moon in the southeastern corner of Pisces the Fish, now nearly 13° east of Mars. As the Moon travels around Earth, it can look to observers on Earth as if it’s “nodding” back and forth — sometimes areas at the limb are easier to see than others. This motion is called libration and tonight, it makes features normally hard to spot on the Moon’s northeastern limb more accessible. With binoculars or a small scope, look at the upper right portion of the lunar disk for three dark spots. These are Lacus Spei, Endymion, and Mare Humboldtianum (closest to the edge).
>    Come back over the next few nights, and you’ll see Humboldtianum slowly disappear in the last days of the month. By the 30th, Lacus Spei and Endymion will appear at the very edge of the disk.
>
>
> Friday, November 27
>    Since last night, the Moon has crossed out of Pisces and traveled through the corner of Cetus, where it passed 3° south of Uranus at noon EST. By sunset in the Midwest, our satellite is now in Aries, about 4.5° southeast of the ice giant.
>    Uranus, currently magnitude 5.7, is visible in binoculars but may be hard to spot against our satellite’s glare. Just over 14° north-northwest of the Moon is Hamal, the Ram’s brightest star; 9.5° southeast is Menkar in Cetus the Whale. Look east-northeast of the Moon to find the Pleiades (M45); how many stars can you see without optical aid? Most observers can easily see five, but seven are visible for those with sharp eyes or dark skies. For the latter, you’ll need to wait a few more nights to give the Moon time to move away from the region. Some experienced naked-eye observers have seen 10 or more stars in this open cluster under the right conditions.
>
>
> Scientists have uncovered new evidence in the mysterious fluorescent debris of the Blue Ring Nebula that may explain how the strange structure formed.
>    The Blue Ring Nebula is a planetary nebula that harbors a central star, known as TYC 2597-735-1. An unusual ultraviolet ring surrounds the star, which astronomers first observed in 2004 using NASA's now-defunct Galaxy Evolution Explorer (GALEX) space telescope. Until now, the formation of this peculiar ring — which is actually invisible ultraviolet light that has been color-coded blue in the telescope images — has largely remained a mystery.
>    “Every time we thought we had this thing figured out, something would tell us, 'No, that's not right,'" Mark Seibert, an astrophysicist with the Carnegie Institution for Science, a member of the GALEX team and a co-author on the new research, said in a statement. "That's a scary thing as a scientist. But I also love how unique this object is, and the effort that so many people put in to figure it out."
https://phys.org/news/2020-11-mysterious-blue-nebula-scientists-fate.html
>    The Blue Ring Nebula is believed to have formed after a stellar collision, which ejected a cloud of hot debris into space. These emissions appear to form a ring around the nebula's central star, as the outflow of material forms a cone shape and the base of one of the cones is oriented almost directly toward Earth.
(Image credit: NASA/JPL-Caltech/M. Seibert (Carnegie Institution for Science)/K. Hoadley (Caltech)/GALEX Team)
>    Using the W. M. Keck Observatory in Hawaii, researchers found that the blue ring is actually the base of a cone-shaped cloud of glowing molecular hydrogen that extends away from the central star, toward Earth. The new observations also show a second cone-shaped cloud that extends from the star in the opposite direction.
>    The bases of the cone-shaped clouds appear to overlap when viewed from Earth, creating the ring shape around the star, Christopher Martin, a physicist at the California Institute of Technology (Caltech) and former principal investigator of GALEX, said in a news conference held digitally on Tuesday (Nov. 17), before the research was made public.
>    The scientists behind the new research believe that the clouds of fluorescent debris formed after a sunlike star collided with and consumed a smaller stellar companion only a few thousand years ago. The recent observations capture a never-before-seen evolutionary phase of a stellar collision.
>    The stellar collision ejected a cloud of hot debris into space. As the debris flew outward, it created a shock wave that, in turn, heated up hydrogen molecules in the debris cloud, producing the ultraviolet emissions scientists first observed back in 2004.
>
>
> Scientists are trying to make sense of a physics-altering collision.
>    Roughly seven billion years ago, two monstrous black holes slammed together in a catastrophic celestial event so intense, it shot a pulse of gravitational waves out across the universe. Astonishingly, those gravitational waves only reached Earth one year ago, and astronomers now believe they've spotted the most powerful black hole collision yet: an event they've dubbed GW190521.
>    Researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) in the U.S. and the Virgo Observatory in Italy first detected the waves—ripples in the fabric of space-time—in May 2019. The two smashed black holes at the heart of the collision were 66 and 85 times more massive than our sun, astronomers report in two papers published last week in Physical Review Letters and The Astrophysical Journal. When they collided, they formed a gargantuan black hole approximately 142 times more massive than our sun.
>    Not only is this likely the most powerful explosion ever recorded, but it proves the existence of a rare class of black holes: intermediate-mass black holes. “Now we can settle the case and say that intermediate-mass black holes exist,” LIGO astrophysicist Christopher Berry of Northwestern University, told National Geographic.
>    A black hole 85 times the mass of our sun theoretically shouldn't exist. It doesn't pair well with the theories researchers have about how stars die. Stars that range from a few times to 60 times the mass of our sun typically burn all of their fuel and eventually collapse in on themselves, forming a "conventional" black hole.
> Stars that are about 60 to 130 times more massive than our sun go out with a bang, but they usually don't become black holes. Instead, they form something called a pair-instability supernova. The heat that occurs during the star's compression is so powerful, all of the material ejected is destroyed. According to the current theory, it simply can't become a black hole. (Supermassive black holes, like the one photographed at the center of M87, form from stars millions to billions the mass of our sun.)

29
download the attached audio file to play the show (ads removed) ~47:30 length; let me know if it plays well for you.  I amplified this version as it seemed the show was a bit low in recorded volume.

JerryW's agenda for the show:
On 11/7/2020 9:49 PM, Jerry wrote:
> Comet Alert
>    Comet C/2020 M3 (ATLAS) glides between Orion the Hunter’s three-star belt and his left knee, magnitude 0.2 Rigel, tonight. After dark, step outside to find the comet just 1° south-southwest of magnitude 3.4 Eta (η) Orionis. According to the Comet Observation database, ATLAS is roughly magnitude 8 — viewable with binoculars or a small telescope. Its coma stretches about 8' across. For the best visibility, consider staying out overnight and watching it into the early morning hours this week.
>    This comet is moving quickly through Orion from night to night, and it’s headed north for a rendezvous with Bellatrix next week. ATLAS has already made its closest approach to the Sun (October 25) and will make its closest approach to Earth on the 14th, when it comes within 0.4 astronomical units of our planet. (One astronomical unit is the average Earth-Sun distance.)
>
Monday, November 9
>    At the feet of the well-known constellation Orion sits Lepus the Hare. Formed by roughly a dozen stars, this dim figure fully clears the horizon just before 10 P.M. local time and is visible even from suburban locations. Some stories depict Lepus as being hunted by the Hunter or his dogs, Canis Major and Canis Minor — and you’ll see the two hounds clearing the horizon shortly after. But alternate tales claim Lepus crouches at Orion’s feet for protection from other hunters that might consider him prey.
>
>    The constellation’s brightest (alpha) star, magnitude 2.6 Arneb, is about 9° southwest of Orion’s right knee, Saiph. (His left knee, Rigel, is much brighter.) But through binoculars, magnitude 3.6 Gamma (γ) Leporis might be the most distinct of Lepus’ stars, with a companion star glowing at magnitude 6 just 97" to the north. The two are slightly different colors, with brighter Gamma A appearing yellower than dimmer Gamma B, which looks more orange.
>
>    Nearby is M79, a globular cluster that sits a little less than 4° south of Nihal (Beta [β] Leporis). One of the few good winter-sky globulars, this densely packed group of some 100,000 stars may once have been part of the Canis Major Dwarf Galaxy — the closest galaxy to the Milky Way that astronomers have found to date.
>
>
> Tuesday, November 10
>
>    Mercury reaches greatest western elongation (19°) from the Sun at noon EST today. The planet is an early morning object, rising about an hour and a half before the Sun. Today, it’s glowing at magnitude –0.5 and is roughly 13° high by 6:15 A.M. local time. Above it, the bright planet Venus is 25° high. With optical aid, you’ll see that Mercury is nearly 60 percent lit and spans 7". Venus, which stretches 13" across, is 84% lit.
>
>    We’ll check back in with these planets later in the week, when the crescent Moon joins them. Our satellite isn’t hard to find, though — it’s northwest of the planets, higher in the sky as it floats near the hindquarters of Leo the Lion. The Moon is positioned this morning on a line drawn between Iota (ι) and Rho (ρ) Leonis, both magnitude 4, and sits south-southwest of the magnitude 3 star Chertan.
>
>
> Wednesday, November 11
>
>    Even as the Leonid meteor shower is ramping up for a treat later this month, the lesser-known Northern Taurid meteor shower peaks overnight tonight and into tomorrow morning. These meteors are debris left by Comet 2P/Encke; they zip through our atmosphere at about 18 miles (29 km) per second. Observers can expect to spot roughly five to 10 meteors per hour during the shower’s peak. Admittedly, that’s not much more than the average background rate of meteors (seven per hour) this time of year, but bright fireballs are more likely during showers.
>
>    The best time to look for shower meteors is late tonight and early tomorrow morning, when Taurus is high in the sky. You’ll find the radiant about 2.5° southeast of the familiar Pleiades (M45). Even if the Northern Taurids put on a poor show, this beautiful open cluster is a rich region to explore with binoculars or any size scope. With the Moon a mere 15 percent lit, it’s also a great night to see if you can spot any nebulosity between the cluster’s brightest stars. This dim, wispy glow comes from gas and dust that reflects, rather than absorbs, the nearby starlight.
>
>
> Thursday, November 12
>
>    The Moon passes 3° north of Venus at 1 P.M. PST. A little more than two hours before dawn, eager skywatchers will find them rising in the east, just over 6° apart. Venus is blazingly bright at magnitude –4 and sits very close to magnitude 4.4 Theta (θ) Virginis in Virgo the Maiden. The two are less than 0.5° apart.
>
>    Before the sky grows too light, look North of Virgo for the Big and Little Dippers — both asterisms within the larger Ursa Major and Ursa Minor constellations, respectively. This morning, the Little Dipper appears upright, which means the Big Dipper appears nearly upside-down. As you look north, you’ll see the Big Dipper to the upper right of its littler counterpart. Directly beneath the Little Dipper is the twisting form of Draco the Dragon, whose alpha star Thuban (located about 10° south of the right-hand edge of the Little Dipper’s cup) once sat above Earth’s north pole as its pole star.
>
>
> Friday, November 13
>
>    The Moon passes 1.7° north of Mercury at 1 P.M. PST. Catch the pair in the hour or so before sunrise this morning in Virgo, where they’re rising in the east, preceding our star. At that time, the delicate crescent Moon stands 5° above Mercury, which glows an easy magnitude –0.7, only slightly dimmer than it appeared just days ago. Mercury now sits just 2° west of magnitude 4 Kappa (κ) Virginis.
>
>    Nearby is blazingly bright Venus, now about 1.5° southeast of Theta Virginis. Glance down a bit and you won’t be able to miss Spica, Virgo’s brightest star (magnitude 1). You should be able to follow the scene well into morning twilight.
>
>
> Mysteries Beyond Neptune.
>
>    Astronomers have discovered 139 new minor planets orbiting the Sun beyond Neptune by searching through data from the Dark Energy Survey. The new method for spotting small worlds is expected to reveal many thousands of distant objects in coming years — meaning these first hundred or so are likely just the tip of the iceberg.
>
>    Taken together, the newfound distant objects, as well as those to come, could resolve one of the most fascinating questions of modern astronomy: Is there a massive and mysterious world called Planet Nine lurking in the outskirts of our solar system?
>
>    Neptune orbits the Sun at a distance of about 30 astronomical units (AU; where 1 AU is the Earth-Sun distance). Beyond Neptune lies the Kuiper Belt — a comet-rich band of frozen, rocky objects (including Pluto) that holds dozens to hundreds of times more mass than the asteroid belt. Both within the Kuiper Belt and past its outer edge at 50 AU orbit distant bodies called trans-Neptunian objects (TNOs). Currently, we know of nearly 3,000 TNOs in the solar system, but estimates put the total number closer to 100,000.
>
>    As more and more TNOs have been discovered over the years, some astronomers — including Konstantin Batygin and Mike Brown of Caltech — have noticed a small subset of these objects have peculiar orbits. They seem to bunch up in unexpected ways, as if an unseen object is herding these so-called extreme TNOs (eTNOs) into specific orbits. Batygin and Brown — in addition to other groups, like that led by Scott Sheppard of the Carnegie Institution for Science — think these bizarrely orbiting eTNOs point to the existence of a massive, distant world called Planet Nine.
>
>    Hypothesized to be five to 15 times the mass of Earth and to orbit some 400 AU (or farther) from the Sun, the proposed Planet Nine would have enough of a gravitational pull that it could orchestrate the orbits of the eTNOs, causing them to cluster together as they make their closest approaches to the Sun.
>
>    The problem is that the evidence for Planet Nine is so far indirect and sparse. There could be something else that explains the clumped orbits, or perhaps researchers stumbled on a few objects that just happen to have similar orbits. Discovering more TNOs, particularly beyond the Kuiper Belt, will allow astronomers to find more clues that could point to the location of the proposed Planet Nine — or deny its existence altogether. Of the 139 newly discovered minor planets found in this study, seven are eTNOs, which is a significant addition to a list that numbered around a dozen just a few months ago.
>
>    The new TNOs were found by astronomers at the University of Pennsylvania using data from the Dark Energy Survey (DES), which was not originally designed to look for distant minor planets.
>
>    Unfortunately, the new objects don’t yet lead to anything conclusive about Planet Nine. The researchers released early results analyzing whether the orbits of the seven newfound eTNOs support the clustering pattern that points to Planet Nine, but so far, they’ve turned up nothing.
>
>    “If this were the first dataset that came out, then no one would have come up with the Planet Nine hypothesis because there appears to be no clustering [in the orbits of the new eTNOs],” says Sako. However, he adds that this doesn’t disprove the existence of Planet Nine either. Their method could uncover other eTNOs that do support the proposed Planet Nine — or even spot the object itself.
>
>
> Snoopy, Where are you?
>
>    All but one of the Apollo program’s used lunar modules either crashed into the Moon’s surface or burned up in Earth’s atmosphere. Apollo 10’s lunar module, Snoopy, is still out there, drifting aimlessly around the solar system, waiting for some future exo-archaeologist to snatch it up for display at the Smithsonian.
>
>    The mission was designed as a rehearsal for the main event on the Moon, but it set records of its own. History glazes over Apollo 10 because of the significance of what followed; however, the crew completed the same tasks as Apollo 11 (minus landing on the Moon).
>
>    And they used Snoopy, the lunar module, as well as Charlie Brown, the command module, to travel farther and faster than any humans have before or since.
>
>    During the mission, Snoopy was jettisoned into space as planned and would have entered orbit around the Sun. However, its location remains a mystery despite efforts by amateur astronomers to search for it using the last known 1969 orbital coordinates. They identified a number of target sites, but so far they’ve been unsuccessful.
>
>    Interestingly, many of the other landers’ exact lunar impact sites — including Apollo 11’s Eagle — are also a mystery that future space explorers may someday find and excavate, like underwater archaeologists uncovering Amelia Earhart’s Lockheed Electra.
>
>
> Seeding Life on Earth?
>
>    A meteorite that landed on a frozen lake in 2018 contains thousands of organic compounds that formed billions of years ago and could hold clues about the origins of life on Earth.
>
>    The meteor entered Earth's atmosphere on Jan. 16, 2018, after a very long journey through the freezing vacuum of space, lighting up skies over Ontario, Canada, and the midwestern United States. Weather radar tracked the flaming space rock's descent and breakup, helping meteorite hunters to quickly locate fallen fragments on Strawberry Lake in Hamburg, Michigan.
>
>    The meteorite held 2,600 organic, or carbon-containing compounds, the researchers reported in the study. Because the meteorite was mostly unchanged since 4.5 billion years ago, these compounds likely are similar to the ones that other meteorites brought to a young Earth, some of which "might have been incorporated into life," Heck said.
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>    The transformation from extraterrestrial organic compounds into the first microbial life on Earth is "a big step" that is still shrouded in mystery, but evidence suggests that organics are common in meteorites — even in thermally metamorphosed meteorites such as the one that landed in Michigan, he added. Meteor bombardment was also more frequent for a young Earth than it is today, "so we are pretty certain that the input from meteorites into the organic inventory on Earth was important," for seeding life.
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> Sent from my iPad


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Outreach & Events / 201026 SBAU radio just caught 18 minutes
« on: November 09, 2020, 03:39:05 PM »
see attached file to download 18 min audio.

show agenda by JerryW:
On 10/24/2020 2:39 PM, Jerry wrote:
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> Monday, October 26
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>    Asteroid 471 Papagena, currently located in the constellation Cetus the Whale, reached opposition at 11 PM PDT last night. At that time, the tiny world is about 40° high above the southwestern horizon, glowing at magnitude 9.5.
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>    If you’re looking to spot Papagena, the nearest stellar signpost is Mira (Omicron [ο] Ceti), which sits 5° north-northwest of the asteroid. Mira is a famous star in its own right — this “wonderful” luminary is a variable star whose magnitude swings between 2 and 10 over the course of nearly 11 months. Its most recent peak in brightness was earlier this month. Careful, consistent observers can chart its changes by revisiting the star every one to two weeks and comparing its brightness with the stars around it. Binoculars or a telescope will do the trick, depending on your options and your location (i.e., the amount of light pollution).
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> Tuesday, October 27
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>    It’s another early morning for observers, but well worth it to catch the Moon passing 4° south of Neptune at 11 PM PDT (Monday). The pair are in the constellation Aquarius, with two magnitude 4 stars — Psi1 (ψ1) and Phi (φ) Aquarii — between them. Neptune, at magnitude 7.8, requires some decent optical aid to see, especially with the gibbous Moon so close. Its 2"-wide, bluish disk will likely appear as a “flatter” star in your field of view.
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>    The distant ice giant is currently nearly 30 astronomical units, or AU, from Earth. (One AU is the average Earth-Sun distance.) Despite its diminutive appearance through your optics, Neptune is actually 17 times more massive than Earth and nearly 4 times as wide; however, it is only 0.3 times as dense as our planet, owing to its icy, gassy composition when compared to our rocky home.
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> Wednesday, October 28
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>    Like the Force, Saturn’s two-faced moon Iapetus has a light side and a dark side. Currently, that brighter side is turned toward Earth, making the tiny, icy moon a little easier to locate as it orbits the ringed planet.
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>    Tonight, magnitude 0.6 Saturn sits about 5.5° east of magnitude –2.2 Jupiter; both are in the southwest among the stars of Sagittarius. Zoom in on Saturn with a telescope to pick out several of its moons — the largest and brightest, Titan, is just under 2' southwest of the planet. Tenth-magnitude Tethys and Dione float east of the planet, with Dione the farther of the two. Rhea, also magnitude 10, is about 30" due south of the eastern edge of the rings. Enceladus, a challenging magnitude 12, lies just 6" northwest of Tethys.
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>    Look due west of Saturn to find Iapetus, glowing near magnitude 10 and about three times farther from the planet’s disk than Titan. As its dark side rotates back into view next month, the moon will dim; the difference in brightness between its two hemispheres is a little more than a magnitude.
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>    For a less-challenging set of satellites, swing over to Jupiter, where all four Galilean moons are on display. Only Callisto is currently east of the planet; on the western side, Ganymede, Io, and Europa line up (from closest to farthest). The orientation of the moons shows just how perpendicular Jupiter’s poles are to its orbital plane — the giant planet is tilted by a mere 3°, much less than Earth’s 23.5°.
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> Thursday, October 29
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>    The Moon passes 3° south of Mars at 9 AM PDT. By the time the pair has cleared the horizon around sunset, they’re just over 4° apart. You’ll find them in the east, rising as the sky grows darker, with Mars just to the upper right of the Moon. The Red Planet, still a bright beacon two weeks after opposition, glows at magnitude –2.2 and appears 20" across.
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>    By two hours after sunset, the face of Taurus the Bull is peeking above the horizon, with his bright red eye, Aldebaran, popping up shortly after. Look directly above the v of the Bull’s nose to find the Pleiades (M45) sparkling in the shape of a tiny dipper. Although this open cluster is often confused with the Little Dipper, its spoon shape is much smaller and more compact than the asterism, located in the north. The Pleiades is a young cluster containing several thousand stars and about 800 solar masses of material. With the naked eye, you may see as many as 12 of the cluster’s stars; binoculars and telescopes will bring out many more. If you’re an astroimager, turning your camera on the cluster is likely to reveal the nebulosity, or glowing gas, strung between the brightest stars.
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> Friday, October 30
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>    The Moon reaches apogee, the farthest point from Earth in its orbit, at 11:45 AM PDT. It will then sit 252,522 miles (406,395 kilometers) from our planet. Our satellite is 99 percent lit and will delight Halloween revelers tomorrow as a Full Moon to light the spooky holiday.
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>    The nearly Full Moon does, however, make the sky brighter and washes out dimmer stars and deep-sky objects. Tonight is a great night to search out some famous asterisms, though: the Square of Pegasus, the Big and Little Dippers, the Teapot in Sagittarius, and the w shape of Cassiopeia. Also still visible is the Summer Triangle, made up of the three bright stars Deneb, Altair, and Vega. High overhead during summer nights, the Triangle is now lower in the west around 8 P.M. local time. Over the next few months, its stars will set completely by sunset and the Triangle will disappear as the winter constellations come out in full force.
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> IapetusSides.jpeg
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> Dark and light
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> Saturn’s moon Iapetus is markedly brighter on one side than the other. This week, the lighter side is facing Earth.
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> Wolf-Rayet are Us!
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>    Astronomers know that our solar system formed about 5 billion years ago from material left over from previous generations of stars. However, beyond that, it gets a little murky.
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>    The prevailing theory is that a nearby supernova explosion compressed a dense cloud of gas and dust until it collapsed in on itself due to its own gravity. As the cloud condensed, it grew hotter and spun faster. Eventually, the center of the cloud grew so hot it began fusing hydrogen into helium and became the star we lovingly call the Sun.
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>    But according to a study published December 22 in the Astrophysical Journal, the solar system instead may have formed inside the dense shell of an enormous bubble within a giant star. The study not only provides a fantastical scenario for our solar system’s formation, but also addresses a long-standing mystery concerning our solar system’s chemical makeup.
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>    The new theory for how the solar system formed starts with an extremely massive star known as a Wolf-Rayet star. Of all the stars in the universe, these stars burn the hottest. Because they are so hot, they also have exceptionally strong stellar winds.
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>    As a Wolf-Rayet star sheds its outer layers – a normal end-of-life process for a giant star – its strong stellar winds plow through its loosely held cloak of material, forming densely shelled bubbles. According to the study, the solar system could have formed inside of one of these bubbles.
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>    Since such a huge amount gas and dust is trapped inside, “the shell of such a bubble is a good place to produce stars,” said Nicolas Dauphas, co-author of the study and professor of geophysical sciences at the University of Chicago, in a press release. The researchers estimate that this stellar-womb process is so effective that it could account for the formation of 1 to 16 percent of all Sun-like stars.
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>    Although the unconventional theory may seem a bit superfluous, the researchers proposed it because it also addresses a long-standing mystery of the early solar system: Why did it have so much aluminium-26 and so little iron-60 when compared to the rest of the galaxy?
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>    Previous studies of meteorite samples have shown that the early solar system was ripe with the isotope aluminium-26, while other studies have shown it was deficient in the isotope iron-60. However, since supernovae explosions produce both of these isotopes, “it begs the question of why one was injected into the solar system and the other was not,” said Vikram Dwarkadas, co-author of the study and professor of astronomy and astrophysics at the University of Chicago.
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>    This is what brought the researchers to Wolf-Rayet stars, which produce lots of aluminium-26, but zero iron-60.
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> Star Spagettified by a Black Hole
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>    “The idea of a black hole ‘sucking in’ a nearby star sounds like science fiction. But this is exactly what happens in a tidal disruption event,” says Matt Nicholl, a lecturer and Royal Astronomical Society research fellow at the University of Birmingham, UK, and the lead author of the new study. But these tidal disruption events, where a star experiences what’s known as spaghettification as it’s sucked in by a black hole, are rare and not always easy to study. The team of researchers pointed ESO’s Very Large Telescope (VLT) and ESO’s New Technology Telescope (NTT) at a new flash of light that occurred last year close to a supermassive black hole, to investigate in detail what happens when a star is devoured by such a monster.
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>    Astronomers know what should happen in theory. “When an unlucky star wanders too close to a supermassive black hole in the centre of a galaxy, the extreme gravitational pull of the black hole shreds the star into thin streams of material,” explains study author Thomas Wevers, an ESO Fellow in Santiago, Chile, who was at the Institute of Astronomy, University of Cambridge, UK, when he conducted the work. As some of the thin strands of stellar material fall into the black hole during this spaghettification process, a bright flare of energy is released, which astronomers can detect.
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>    Although powerful and bright, up to now astronomers have had trouble investigating this burst of light, which is often obscured by a curtain of dust and debris. Only now have astronomers been able to shed light on the origin of this curtain.
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> “We found that, when a black hole devours a star, it can launch a powerful blast of material outwards that obstructs our view,” explains Samantha Oates, also at the University of Birmingham. This happens because the energy released as the black hole eats up stellar material propels the star’s debris outwards.
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>    The discovery was possible because the tidal disruption event the team studied, AT2019qiz, was found just a short time after the star was ripped apart. “Because we caught it early, we could actually see the curtain of dust and debris being drawn up as the black hole launched a powerful outflow of material with velocities up to 10 000 km/s,” says Kate Alexander, NASA Einstein Fellow at Northwestern University in the US. “This unique ‘peek behind the curtain' provided the first opportunity to pinpoint the origin of the obscuring material and follow in real time how it engulfs the black hole.”
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>    The team carried out observations of AT2019qiz, located in a spiral galaxy in the constellation of Eridanus, over a 6-month period as the flare grew in luminosity and then faded away. “Several sky surveys discovered emission from the new tidal disruption event very quickly after the star was ripped apart,” says Wevers. “We immediately pointed a suite of ground-based and space telescopes in that direction to see how the light was produced.”
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> The Big News of last week...A Fly-by-Grabbing
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>    WASHINGTON — NASA’s OSIRIS-REx spacecraft collected so much material from the surface of the asteroid Bennu that the lid of its sampling head is jammed open, causing material to leak out and changing the agency’s plans for the mission.
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> At a media briefing called by NASA on short notice Oct. 23, three days after the spacecraft touched down on the asteroid, officials said that images taken of the head of the sampling device, called the Touch-And-Go Sample Acquisition Mechanism (TAGSAM), showed material leaking out of the container from a gap in a Mylar diaphragm that is supposed to seal the bottom of the head.
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>    “I am highly confident that TAGSAM was success, that it collected abundant mass: definitely evidence of hundreds of grams of material, and possibly more,” said Dante Lauretta, principal investigator for OSIRIS-REx at the University of Arizona. “My big concern now is that the particles are escaping because we were almost a victim of our own success.”
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>    Those images show a cloud of particles outside of the TAGSAM, floating away from it at about one centimeter per second. He estimated that the material visible for those images had a mass of 5 to 10 grams. He added it is not likely a “steady state” mass loss since the head was moving around when those pictures were taken, helping particles escape through the gap in the diaphragm. Star tracker cameras on the spacecraft, which also detected the particles, saw much less after the head was “parked” on the side of the spacecraft.
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>    The concern that more material might leak out of the sample head, though, has prompted NASA to change plans for the mission. Lauretta said that a maneuver planned for the weekend, where the spacecraft would be slowly spun up to measure the change in its moment of inertia and thus the mass of the sample material, has been canceled. Instead, planning is underway to stow the samples in a canister inside the spacecraft, where they will be sealed for return to Earth.
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> Sent from my iPad

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