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[TomT]

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.