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Autoalign with a CEM60?

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#1 hrgreen

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Posted 22 April 2018 - 04:44 PM

My interest is in visual only.  In a previous incarnation, I owned a CGEM mount  and StarSense for my 9 1/4 Celestron.  I didn't like the CGEM so well, as it was heavy to carry and set up, noisy, and had a fair amount of backlash.  The polar scope was a joke.  So I upgraded to a CEM60, which I like much better.  It weighs about 60% as much, and runs quietly, smoothly, and with little backlash.  GPS is built-in and polar scope easy to use if I can see Polaris.

 

But I'm getting up in age.  Deteriorating vision leaves me sometimes unable to indentify alignment stars in a reasonably short time, and going back to a CGEM II/StarSense would be too much for me to handle alone.  I dearly wish a StarSense or equivalent could be used on this mount.  Has anyone figured out how to do this?   I've heard that using a laptop to control the mount via Ascom and using Astro Tortilla and SharpCap with a small CCD camera can do the same thing.  However, I'm not familiar with any of the SW, and would need coaching on how to put things together.  Thanks.

 

Hal



#2 rmollise

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Posted 22 April 2018 - 04:57 PM

My interest is in visual only.  In a previous incarnation, I owned a CGEM mount  and StarSense for my 9 1/4 Celestron.  I didn't like the CGEM so well, as it was heavy to carry and set up, noisy, and had a fair amount of backlash.  The polar scope was a joke.  So I upgraded to a CEM60, which I like much better.  It weighs about 60% as much, and runs quietly, smoothly, and with little backlash.  GPS is built-in and polar scope easy to use if I can see Polaris.

 

But I'm getting up in age.  Deteriorating vision leaves me sometimes unable to indentify alignment stars in a reasonably short time, and going back to a CGEM II/StarSense would be too much for me to handle alone.  I dearly wish a StarSense or equivalent could be used on this mount.  Has anyone figured out how to do this?   I've heard that using a laptop to control the mount via Ascom and using Astro Tortilla and SharpCap with a small CCD camera can do the same thing.  However, I'm not familiar with any of the SW, and would need coaching on how to put things together.  Thanks.

 

Hal

 

No, and likely no one will be able to. Even making the StarSense work with the company's own SynScan mounts required a rather sophisticated interface box. If you've got a lot of electronics experience and Mr. Carlson's Lab at your disposal, you might do it, but it wouldn't be overly trivial. If you are visual only, you really would find plate solving and such to be a hairline reducer at best.

 

Some work-arounds?

 

I thought I was going to miss my CGEM for this very reason when I replaced it with a Losmandy GM811 (due to a back injury). That StarSense sure was nice (I do still use it with my AVX). But I found out it just wasn't that big a deal giving it up. The normal Celestron alignment requires as many as 6 stars total for a good alignment. And you are best off using the stars the computer picks. I found, however, that with the Losmandy, and I suspect with your CEM60, I could align on three conveniently located and prominent stars on the side of the Meridian I was working on. Like Capella, Rigel, and Aldebaran in the west right now. Gotos are just fine assuming I've taken care with my polar alignment. Good enough for imaging with a DSLR at 1500mm focal length (as in getting the target on the chip every time) or so. Actually, gotos are also quite good enough for visual use on the opposite side of the Meridian with a medium-low power eyepiece without adding any "eastern" stars. 

 

Another way to approach this? If you've got a secure backyard and can leave your telescope setup through stretches of clear weather under a good cover, just hibernate it at the end of the evening, and resume the next night with no need for an alignment at all. smile.gif


Edited by rmollise, 23 April 2018 - 08:56 AM.


#3 bmhjr

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Posted 22 April 2018 - 05:12 PM

Here is a new gadget that will sync the mount, among other things. You would need to add a guide camera. Hopefully they will release more info, price, soon.

https://www.cloudyni...989-zwo-asiair/

#4 DuncanM

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Posted 22 April 2018 - 06:24 PM

My interest is in visual only.  In a previous incarnation, I owned a CGEM mount  and StarSense for my 9 1/4 Celestron.  I didn't like the CGEM so well, as it was heavy to carry and set up, noisy, and had a fair amount of backlash.  The polar scope was a joke.  So I upgraded to a CEM60, which I like much better.  It weighs about 60% as much, and runs quietly, smoothly, and with little backlash.  GPS is built-in and polar scope easy to use if I can see Polaris.

 

But I'm getting up in age.  Deteriorating vision leaves me sometimes unable to indentify alignment stars in a reasonably short time, and going back to a CGEM II/StarSense would be too much for me to handle alone.  I dearly wish a StarSense or equivalent could be used on this mount.  Has anyone figured out how to do this?   I've heard that using a laptop to control the mount via Ascom and using Astro Tortilla and SharpCap with a small CCD camera can do the same thing.  However, I'm not familiar with any of the SW, and would need coaching on how to put things together.  Thanks.

 

Hal

Astroart 6 can do the same. I haven't done it but it would go like this if you just want assisted alignment without using Ascom mount control. The basic technique should work with any mount and platesolving package.

 

 

 

You have a small guidescope fitted with a guidecamera (typically a ~1 degree field). The guidescope/camera is centred to the main OTA and the camera is controlled by AA6* or alternately the camera saves to a folder and you load the image into AA6 - you can use the unlimited time free demo version of AA6 for this, BTW.

 

You start from the home position (normal procedure) and slew to your first alignment star and the CEM60 HC will give an estimated RA/Dec = to the alignment star's RA/Dec.

 

Take an image with the guidescope.

 

Ask AA6 to plate solve with the alignment star as the target for the image (AA6's plate solve engine will accept star names). AA6 plate solves and then gives the RA and Dec. You compare the stated HC Ra/Dec to the actual RA/Dec and note the difference:

 

example: Target RA/Dec = 18h 35min/ 47d 28min and actual RA/Dec = 17h 58m/49d 01min.

 

Variation = minus 37min/RA and plus 1d 33min Dec

 

 

then using the slew buttons on the HC increase the RA by 37min and reduce Dec by 1d 33 min and the target star should be nearly centred. Use a crosshair overlay on the display, centre the star and accept the alignment on the HC, then slew to the next suggested alignment star using the HC.

 

I know I struggle with initial alignment as well and I just worked out, above, a simple method to assist me!

 

* You setup the plate solve engine by inputting the camera and guidescope parameters into the settings menu and select a suitably large target area (say 9 x 9 degrees).


Edited by DuncanM, 22 April 2018 - 06:41 PM.



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