The SBAU Forum

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Very clean Televue Oracle3 refractor with case. As my eyesight is slowly going south the scope has seen little use in the past few years.

A lost leader for Televue, the Oracle 3 the scope is a:
76mm apochromatic lens, F/7.4.

Visuals are lst class. With the correct solar filters it makes an excellent solar imaging scope as well.

Include:
Case
2 inch focuser and 2 inch diagonal
2 inch barlow with a 1.25 eyepiece insert
Red dot finder
30mm 2 inch Erfle eyepiece.

$800.00

Also posting a C8 otafor sale in another post

http://www.dosgatos.com/au/equipment/tv/oracle-1.jpg
http://www.dosgatos.com/au/equipment/tv/oracle-2.jpg
http://www.dosgatos.com/au/equipment/tv/oracle-3.jpg
http://www.dosgatos.com/au/equipment/tv/oracle-4.jpg
http://www.dosgatos.com/au/equipment/tv/oracle-5.jpg

Sold 6-16-19 to TomT
Hi Everyone:  i have a Celestron C11 11- inch Schmidt-Cassegrain tube assembly for sale.  It comes with illuminated 9 X 50 finder scope, 1-1/4" and 2' diagonals. and 40 mm eyepiece, and Bob's knobs for easy collimation.  It has a CGE type mounting dovetail.  All in fine condition, clean optics.  Weight is slightly less than 30 lb.  Also I can provide components for mounting this assembly on a Dobson-type base.   I'd like to get $800 for all of the above.  I don't want to ship this equipment.
Please contact me at        i can provide photos attached to return email 
Gail Massey

-------- Forwarded Message --------
Subject:    Meade Schmidt-Cassegrain 10” LX200 Telescope
Date:    Wed, 24 Apr 2019 14:33:15 +0000
From:    Ron Skinner <ron.skinner@moxi.org>
To:    Ron Skinner <ron.skinner@moxi.org>
Hello Santa Barbara astronomers,
I have a Meade Schmidt-Cassegrain 10” LX200 telescope and equipment for sale that was purchased new in 2000. It is in excellent condition. I prefer to sell everything together and am asking $1,500. Here is a list of the equipment:
    Meade Schmidt-Cassegrain 10” LX200 f/10 telescope
    Meade standard field tripod
    Beigle/Bryant Engineering ScopeSaver
    Bonney Lake Astro Works Milburn Wedge
    1206 electric focuser
    Meade 18V DC power supply
    1812 DC adapter (12V to 18V)
    610 Dew cap
    8 x 50 mm finderscope
    Telescope carry bag
    07182 eyepiece holder
    07202 diagonal prism
    07067 plossl 9 mm illuminated reticle eyepiece with 6’ cord and plug
    07270 2 x telenegative barlow lens
    07175-02 26 mm super plossl
    07173-02 15 mm super plossl
    07171-02 9.7 mm super plossl
    07170-02 6.4 mm super plossl
    Color filter sets 1, 2, 3 (07530, 07529, 07528)
    Nebula filters 908, 908B, O-III
    Original Meade manual
    Misc star charts
If you are interested please text or call me at (805) 748-5005. If you know someone who might be interested, please forward this email to them.
Thanks, Ron
Ron Skinner, Director of Education
MOXI, The Wolf Museum of Exploration + Innovation
125 State Street, Santa Barbara, CA 93101
Office: 805.770.5004
Web: moxi.org   |  @MOXIsb

> On Mon, Mar 25, 2019 at 10:51 PM bkm <spamcollector@cox.net> wrote:
>>     Bob,
>>     Tonight I did an experiment.
>>     In the past several nights when I attempted to set up, humidity won. The relative humidity last night was 82%.  Both the 11" dark carbon fiber scope tube and the dark blue astronomy chair seat got wet from dew.   Light colored items, like the white Pentax finder scope, did not accumulate dew.
>>     Celestron paints the OTA's of their EDGE and Rowe-Ackermann white.  Coincidence?
>
>     Today on the KZSB Baron Ron Heron AU radio program, I said that the sky temperature is about -4° C (24.8° F).    Right now, the sky is mostly clear, and I just radiometrically measured its temperature overhead at 19.2° F.  The air temperature is 57° F.
>>     Long story short, the fourth-power Stefan-Boltzmann law applies: radiative heat loss goes as the difference of the fourth powers of the objects temperature (in Kelvin), times the emissivity of the objects (emissivity + reflectivity = 1).  Dark objects have higher emissivity than light objects.  Polished aluminum has an emissivity of 4%, i.e., 96% reflective.  Objects with high emissivity lose more heat to the cold night sky than less emissive objects.  Losing heat to the night sky can cool highly emissive objects to below the air temperature and make them preferentially susceptible to dew formation.
>
>     My experiment was to surround the 11" optical tube with a white paper "muffler".  I also covered the astronomy chair seat with with a white paper towel.  After an hour, I checked on dew formation.  There was no dew on either the OTA or the astronomy chair seat.  The black metal frame of the astronomy chair was wet with dew.  The relative humidity was 91%!
>
>     I've ordered white Naugahyde to cover the astronomy chair seat, and to place around the 11" OTA.  The Naugahyde will be wrapped around the carbon fiber middle of the OTA and taped back on itself, like the paper towels that are now attached.
>>     I'll report on the success (or failure) of the white Naugahyde addition.
>>     You are lucky that Scottsdale has low humidity.
>>     Regards,
>>     Bruce

On 3/26/2019 12:29 AM, Tom Cez wrote:
> That is amazing...but I bet the white paper towel is pretty wet!
> Great detective work!
> TT
   
Re: humidity, dew, and object color
bkm   9:19 AM (58 minutes ago)
to me, Robert, Jerry, Chuck
Tom,
No, the white paper towel was dry on both the OTA, and the astronomy chair seat, even with 91% RH!  Likewise, the top of the stainless steel railing at the front of my deck was also dry, as the polished stainless has high reflectivity.
Case proved.  I should have radiometrically measured the OTA temperature before and after application of the white paper towel, unfortunately, hindsight is 20/20.
The paper towel is the new radiative surface of the OTA, and it emissivity is significantly less than the black carbon fiber OTA body; hence, the paper towel and OTA body are at a temperature more approximating the ambient air temperature.
The OTA now radiates its heat to the paper towel, which has high reflectivity, and the OTA heat is reflected back to the OTA.  The OTA goes to a temperature that is warmer than would occur without the paper towel.  Remember emissivity + reflectivity = 1.
Dew forms on surfaces that are colder than the ambient air temperature.  It is for this reason that dew heaters work.  They raise the temperature of the optics a few degrees above ambient air temperature.
Consider that backpackers oftentimes carry an aluminized Mylar sheet that is folded into a small rectangle called a space blanket.  Should they get stranded in cold weather, the Mylar sheet can be unfolded an used for thermal protection.  I have such a folded Mylar sheet in my backpack.
Likewise, fire fighters wrap historic back-country buildings in an aluminized Mylar blanket to protect them from advancing wildfires.
Backcountry firefighters carry a big aluminized Mylar pouches that is all folded up into a small package.  If they get trapped by the advancing fire, they unfold the pouch and climb inside for protection.
Bruce

Re: Happy Holidays
Mike Chibnik
Sat, Dec 29, 2018, 10:34 AM (3 days ago)
to bkm, me, Cezanne, TomT, Tim, Tim, Tom, Richard, Mike, Mark, Jerry, christopher, emilanes
COMET_46PWirtenan48.jpg
To all who asked how it took my images:
The first two were taken using my 80mm flourite Megrez using the CDS-600 camera.  The exposures for the Horse head nebula was 5 min exposures for a total of 15 min.  The comet pictures used 60 sec exposures as I haven't learned how to use the offset tracking with the Mesu-200 mount.  With a suggestion from Mark the Polemaster I've been able to get polar alignment that's nearly dead on so 5min exposures with the Megrez is no issue.   I used 48 - 60 sec exposures for that.  Attached to this new email is the comet using my C-8 fro a close in image.  It also used 60 sec exposures.  I have to admit that there didn't seem to be a difference in the pictures between the Megrez and C-8, maybe just a slightly larger nucleus.  As a matter of fact when I'm viewing the comet using binoculars I've been seeing something similar with just a hint of a smaller nucleus.  All images taken are with the new Opti-Pro light pollution filter which results in much darker backgrounds in spite of the new LED lights that have been installed.  The only issue is that when I try to use flats I get a rainbow effect with the filter not seen before. 
Mike


On Sat, Dec 29, 2018 at 12:44 AM bkm <spamcollector@cox.net> wrote:
    Tom and Mike,
    Seasons Greetings from the Isla Vista Shores.
    Tom, I like your early evening shot and the blue background.  Nice crisp star images.  The Pleiades have great detail.  Ally's Braid shows up nicely.
    Mike, your Horsehead Nebula picture did not survive going through Tom's reply.
    Here are my pictures of 46P/Wirtanen taken with my Nikon D500, C11 scope (2,800 mm focal length), and Orion Atlas Pro mount in sidereal tracking taken December 27th and 28th.
    The night was clear, low humidity (46%), and cold (41°F).  It was also windy, so the clear night sky wiggled.  I was up the entire night, and went to bed at 5AM.  Venus was brilliant then, low in the east, sort of like a first-quarter moon, and extremely wiggly.  I didn't take pictures.
    I found and photographed Comet Wirtanen.  It was high overhead between Auriga and Ursa Major.  All photographs that follow are single exposures.  This photograph was 30 seconds, ISO 6,400.  More photographs later.
>
I've done a fair amount of work on the mount electronics, and my alignment and tracking are now much better.
    1) Small 3-amp circuit breakers were added to the battery output connectors, as I had read on Cloudy Nights about a heater controller fire using just a battery power supply.
    2) Objective and eyepiece heaters were added to the Pentax 75mm SDHF APO finder scope.  When it was really humid (85%) at Bacara, both the unheated Pentax objective and eyepiece fogged up.  I already have an Astrozap eyepiece heater and dew shield on the C11.
    3) The Astrozap heater controller failed on both outputs simultaneously (no heat).  There was a gate-to-drain short in both big output FETs (field effect transistors) that drive the heating elements.
    In the controller, FET's are used as electronic switches to provide pulse-width modulated voltage to the heaters (either 12-volts, or 0 volts, variable duty cycle at a 400 Hz rate).  The failure was characteristic of electro static electricity damage (ESD).  The Astrozap controller has no protection from ESD.  I suspect the ESD damage occurred at Kings Canyon, where the relative humidity was only 19% - perfect for static electricity buildup.  Voltages in excess of 2,500 volts can easily be generated by clothing brushing against conductors, like dew heaters and scope mounts.  When the dew heaters with 2,500+ volts stored static charge are plugged into the Astrozap controller, the 55 volt breakdown rating of the FETs is exceeded, and they catastrophically fail.
    I added protection on both outputs and the 12-volt input using 27-volt TransZorbs.  Also, the output FET's were oscillating at very high frequency, a well known problem.  The solution was to add small resistors in series the the FET gates.  I also posted on Cloudy Nights about the problem.  Here is a picture collage of the components added to the pc board that is inside the Astrozap box.  It works well now.
>
The scope collimation was tweaked (it was slightly off).
I found that my mount was not well counterbalanced, which screwed up initial alignment.  I think the stepper motors lose steps with unbalance.  I also read on Cloudy Nights, that higher supply voltage helps eliminate the step skipping (like 15 or 18 V).
Heavens Above provides Comet Wirtanen ephemeris for the current date and  time: https://www.heavens-above.com/comet.aspx?cid=46P .  I got good initial mount alignment (about 4-minutes of arc from the CNP), and put in the RA and dec specified from Heavens Above.  Voila! there was Wirtanen.  Once I put my camera on the C11, I only had the Pentax 75mm SDHF APO finder scope with 20 mm 72° SWAN eyepiece for centering (25 power).  In the finder, Wirtanen was only visible as a smudge using averted vision.  Once I got it in view in the camera, centering was easy.  I ran the camera ISO to 102,400 and took 1-second exposures, and used the mount RA and dec buttons to center the comet in the camera display.
I wasn't aware of just how much turbulence fuzzies up images.  Here is a side-by-side comparison of Wirtanen taken at 1 second, ISO 102,400 and 30 seconds, ISO 6,400.  The 1 second exposure is noisier, but the stars are crisp.
>
Tonight, I was going to take pictures at ISO 204,800, or 409,600.  I can go to ISO 1.64 million, but these images are noisy. 
Tonight, even though the humidity is 54% and the temperature 46°F, the sky was not particularly clear.  I didn't set up.
During the astro photo session last night, I noticed that Wirtanen moved from picture-to-picture.  The D500 controller was then set to take a sequence of 30 second exposures at 1-minute, 15-second intervals.  The D500 was set for long exposure noise reduction.  It takes the picture, then immediately takes the same exposure with the shutter closed.  The second picture is subtracted from the first in the camera.  I also had the camera set for 2-second shutter delay mode, i.e., it raises the mirror, waits 2-seconds (for mount vibration to settle), then takes the exposure.  Thus, an exposure and noise reduction takes about 1-minute, 4-seconds.
Here is a collage of these pictures.  The comet can clearly be seen to move from frame-to-frame.  I didn't blacken the background or use star masks because I wanted to preserve the diffuseness of the comet.  The night sky was light polluted enough from Goleta's new bright LED streetlights, that neither the ion or dust tails were visible.
>
    Enjoy,    Bruce

    On 12/28/2018 10:50 PM, Tom Cez wrote:
>     Mike,
>     Very nice shots.  What is the camera that you are using?  Did you track the comet (46P/Wirtanen?) & for how long?
>     Attached is a 8 second wide shot with the faint comet between the Hyades and Pleiades, Dec 15 early evening east, iso12800, Olympus OM-D EM5II, adjusted with Windows 10 Photo program.
>     Tom Totton
>
>     On Fri, Dec 28, 2018 at 3:31 PM Mike Chibnik <chibnikm@gmail.com> wrote:
>         If I don’t have a chance to give you a call I want to wish you all a Happy New Year.
>         After all the fires, smoke, rain and winds I managed to get some imaging in.  The one thing that I’m learning about the one-shot CMOS camera I have is you need enough exposure to get into the area for decent detection while trying not to saturate the pixels which will cause you to loose color rendition.  The Horse Head Nebula image shown is a stack of three five minute exposures.  This gave much better results than stacking 30-60 min of 60-120 second exposures.  The main reason for my reluctance to try 5 min and longer exposures was due to the fact that all exposures were unguided.
>         With respect to scope making I’m coming up with a new Foucault light source using a fiber optic jumper and a high power green led source.  I’m looking into figuring how to couple more light into the fiber without having to resorting to an expensive GRIN lens.  I hope the point source will give better Mirror readings .
>         Again Happy holidays from the Sacramento Delta
>         Mike

Happy New Year.

I looked out when I awake at 5:30 this new year's morning, and was surprised and pleased to see the Moon and Venus in conjunction.  Please see the attached photo collage of the occurrence taken with my Nikon D500 camera with lens focal lengths from 18mm to 500 mm, all handheld.  Notice the Moon and Venus are both in phases as shown in the second attachment.

Enjoy,

Bruce Murdock

, rough program notes.txt
--download the attached file [below] and play back on your computer...commercials have been removed

00:00.000  B-mention JW, TT, BM SBAU coming in
00:17.602  B-Quorum SBAU soon
00:25.021  B-yesterday was armistice day, veterans day, JW-WWI war to end all wars. B-but led to WWII, Vimar Republic.  TT-Oumuamua light sail?  JW-not sure of shape if needle or pancake, only 2 dimensions.  B-Hawaii telescope? JW-14K ft high.  JW-maybe pocket of CO2 popping off.  CMcP w/ Pat Bday.
04:55.161  Donny TT-view to ocean from Victoria down SB st.
05:29.346  Donny traffic, pool playing nuns
06:49.501  B-Walter Cronkite voice, raise it high, then you drop.
07:16.558  KZSB voices SBAU
07:21.359  Earth & Sky mass of the Milky Way may be 1.6T solar masses [does this include dark matter?].
08:51.696  "
09:21.518  TT-volunteering planetarium, Javier teaches SBCC astronomy, Sean Kelly star party, Mezas helping always.

11:29.678  music: "it was a calm & cloudless night...1609 Galileo.." B-did he see crescent moon? JW-he made drawings of all the moon phases.  Intros TT, food, TT-depends on members.  December meeting Tessa will do a talk.  Javier not at meetings?  TT-works late  on Thursdays, so burned out by Friday.  B-lost Adrian Lopez, at JPL.  B-book an astronaut? Buzz light yr based on Buzz Aldrin? must be a toy.  JW-JPL, Ames RC provide speakers. B-still test rockets at JPL?  JW-no, but used to up against the mtns, moved testing to White Sands. JW-ph msg fr TT.  B-Mercury probe.  JW-another lander to Mars TT-Insight Mission.  B- 58 types of topography on Mars.  B- 188 members.  B-ArtH missed on Saturday. B-Holiday dinner Flightline.  B-What is up?  JW-what would you like to know?  B-probes?  TT-Juno, Insight, Mercury [BepeColumbo?], Parker mission around Sun. Look at Corona. JW-protons, electrons from Sun.  TT-solar wind.  JW-flags on moon are bleached white.  B-moon like asphalt?  JW-little color on moon if photo saturated. green--TT-must be trees on moon?  B-backside of moon not the same as front. JW-Russian named craters on back. TT-why Russian? JW-they were 1st to see backside.  Bacara non-public outreach mentioned. music: Gato Europa.

22:14.260  music: "it has been a long road gettin from here to there..." B-what is this? TT-got to have faith not going to be hit by an asteroid traveling thru the universe.  Star Trek Enterprise show.  B-William Shatner on Dr. Oz, 85 yrs old.  Cosmic rays, blocked by atmosphere.  B-carbon dioxide.  JW-we know how to heat up planets. magnet in front of Mars.  B-someone pushing Nasa to do Mars mission.  Elon Musk. Tesla orbits Sun. B-it is painted red? JW-it will decompose. BFR.  spacesuits.  JW-takes research to make long lasting materials.  SPRR tested yellow in Wyoming best paint.  Nasa has rule that nothing can go into space without being in space before, catch-22.  B-critics said landing on moon, improvising items? Nasa wanted to minimize mechanisms to avoid failures.  New Horizons needed to tip to pan camera on Pluto mission.  Brilliant risk management program.  TT-James Webb defects.  JW-build up and test at each level.  unfolding heat shields tore, but passed at earlier time.  cause 2yr delay to 2021 launch.  B-position of JW telescope 1M from earth.  JW-keep out of Earth heat signature. Lagrangian L2? point gravity of Sun/Earth balance. Solar orbit.  sensor cooled by liquid He. music: Gato B Europa.

37:56.039  music: "as a spaceship flies, thru the endless...black hole" B-acient Greek on stars, people names on probes?  TT-Juno mission, JW-Hubble, Keck [https://en.wikipedia.org/wiki/William_Myron_Keck#Philanthropy founded:Superior Oil Co], Hale 200" telescope conceived by him.  B-Sagan, Tyson names?  JW-landing site on Mars is the Sagan site.  Need to be dead.  TT-Curiosity landing was complicated.  B-why not use landing balloons? JW-too heavy.  B-Russians got landing on Venus, US did not.  TT-ballooning around Venus? JW-Venus might have been liveable  initially.  B-carbon dioxide.  TT-33% increase on earth last 100 years. JW-may be last generation on earth to be able to reverse problem.  JW-US govt has known about global warming since Kennedy.  Military is planning for that future no matter the politics.  B-Maine lobsters diminishing, moving N.  music: kazoo.

45:31.654 music: "long road getting from here to there"  B-ph# mighty 1290.  Future of mankind...what is coming up?  TT-school science nights.  Westmont why refractor better than reflector?  JW-contrast better,  not diffraction limited.  B-Mt. Wilson big  telescopes etc, warm room off the side, but Westmont no? JW-Westmont does have room below, and JW runs scope at home from inside the house.   Hale telescope had photo plate that required manually moving for fine control.  B-small telescopes cannot compete with Hubble.  music: "once i had enuf of a mass, i became a star of gas..."

53:10.760  music: GatoB Europa.  B-lost in space, danger will robinson.  JW-First Man movie was good, chick flick switching w/ guy flick.  B-did not like Ryan Gosling to be Neil Armstrong.  Val Kilmer looked like Jim Morrison.  TT-telescope workshop...takes 40hrs... JW-if no "go-backs".  B-how does grinding work?  JW-top disk hollows out due to more gravity on its center, D/3 stroke, center over center.  hogging out is chordal stroke.  Then pitch lap w/ cerium oxide polish.  B-thot u did lenses the size of manhole covers?  JW-up to 18".  TT- do not buy from Costco, get 8" dob from Amazon  B-sbau.org
59:38.586 end

Bruce,
Just noticed your reply...I will email or call you on scheduling a reassembly....Thanks for your interest!
Silly to just have it sitting in front of my face.   Nope, did not mark lenses before I realized I goofed up.