Testing plate-solving

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Neil
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Joined: Tue Feb 14, 2017 8:00 pm
Location: Cardiff, UK.

Testing plate-solving

Post by Neil » Tue Aug 08, 2017 10:27 am

Hi,
I am dipping my toes into plate-solving using Sharpcap and the EQASCOM simulated mount (Currently downloading 20Gb of index files!). In order to test the system off-line, is it possible to load up an image to platesolve via the Sharpcap app instead of expecting Sharpcap to take a live image? I'm thinking that I could point the simulated scope (using Stellarium) within 15 degrees of the target in the stored image to see if the scope is moved to the target.

Cheers,

Neil.

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admin
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Re: Testing plate-solving

Post by admin » Tue Aug 08, 2017 8:05 pm

Hi Neil,

yes, use the Test Camera 1 camera, which has an Image 'Browse' button in the controls where you can select an image, then as you say point the simulator to roughly the right area and solve.

cheers,

Robin

Neil
Posts: 11
Joined: Tue Feb 14, 2017 8:00 pm
Location: Cardiff, UK.

Re: Testing plate-solving

Post by Neil » Fri Aug 11, 2017 1:11 pm

Ok,

I can load an image I have taken, and "All Sky Plate Solver" will solve it as being NGC6826, giving the RA and Dec as shown.
All Sky Plate Solver.JPG
All Sky Plate Solver.JPG (147.97 KiB) Viewed 97 times
Using the SharpCap I load the same image using Test Camera 1 (Deep Sky), then I slew the Simulated scope to near enough the same RA and Dec and it will not resolve. What am I missing?
Sharpcap solve.JPG
Sharpcap solve.JPG (154.45 KiB) Viewed 97 times
I fully expect a facepalm here, I feel I am misunderstanding something basic!

Cheers,

Neil.

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Re: Testing plate-solving

Post by admin » Fri Aug 11, 2017 8:29 pm

Hi Neil,

I suspect it all comes down to the parameters passed to the the 'solve_field' plate solving engine by the two different programs. SharpCap has a hardwired set of parameters regarding things like star detection, where ASPS may use different values.

If you look in the SharpCap log after running your test you will see all the output from the plate solve engine which should include a line saying how many stars it found (it will say something like 'SimpleXY found NNN sources'). Numbers from 20+ to 100 or so here are usually good - if you are only seeing a very low number then it means that the parameters SharpCap is using are not finding enough stars.

Feel free to share the frame you are using if you want.

cheers,

Robin

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