Plate solving problem - Forums

Topic starter

Frequent contributor

Mar 26, 2025

Hello,
I am having a plate solving issue and I'm hoping someone has some ideas. I am using NINA with ASTAP the primary PS with astronomy.net as the backup.
My equipment is an ASI2600MC, Edge 9.25" at 2350mm(no reducer).
When it slews and attempts to Plate solve, ASTAP fails and the plate solve is then handed over to astronomy.net which succeeds(but very slow).
I have the largest database of stars for ASTAP, the focal length of the scope is entered correctly, I'm using a 10 seconds for the exposure and the filter used is a light pollution filter. I'm not sure why it is failing with ASTAP unless the FOV is too small, since it is 34"?
If it is the FOV, do I just use astronomy.net or is there a solution?
thank you

andrea tasselli

Frequent contributor

Mar 26, 2025

What catalog did you use?

andrea tasselli

Frequent contributor

Mar 26, 2025

And are you in focus?

ScottF

Topic starter

Frequent contributor

Mar 26, 2025

andrea tasselli:
What catalog did you use?

D80

Tony Gondola

Frequent contributor

Mar 26, 2025

I don't have a solution for you but my experience with ASTAP through NINA was for a reason I could never figure out, very unreliable. Sometimes it would work and a solve and 30 min. later it would fail to solve for a re-center command and shoot me out to astronomy.net. I started to get consistent results when I switched the main solver to Platesolve3 so you might give that a go.

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ScottF

Topic starter

Frequent contributor

Mar 26, 2025

andrea tasselli:
And are you in focus?

Yes, autofocus routine is run first.

ScottF

Topic starter

Frequent contributor

Mar 26, 2025

Tony Gondola:
I don't have a solution for you but my experience with ASTAP through NINA was for a reason I could never figure out, very unreliable. Sometimes it would work and a solve and 30 min. later it would fail to solve for a re-center command and shoot me out to astronomy.net. I started to get consistent results when I switched the main solver to Platesolve3 so you might give that a go.

Maybe I will give that a try. I used to use platesolve3 when I used sequence generator pro.

andrea tasselli

Frequent contributor

Mar 26, 2025

With D80 you should be able to plate-solve in nearly all circumstances unless the focus is poor or the seeing is VERY poor. But using platesolve3 could be a away forward but I doubt it is going to be any better than ASTAP. Can you send us a frame that failed to solve to see what the issue is like on our side?

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Kyle Goodwin

Mar 27, 2025

I have no idea which (if any) of these would apply to your situation, but to give you some things to rule out, here are the most common reasons an ASTAP solve fails:
1. The telescope isn't pointing roughly where it says it is. (The first solve on astrometry.net would sync it and subsequent solves would work.)
2. The image scale is incorrect. (You said the correct focal length is entered, but what about correct pixel size?)
3. The exposure is too short. (You said 10 seconds, that should be way longer than needed.)
4. FOV is small and has few stars. (Probably not a problem with D80 and 10s exposures to get fainter stars, but I'd also bin2)

Beyond those I'd need to see a sample of the image (and critically, the FITS headers from it) as well as your NINA/ASTAP config.

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Alfredo Beltrán

Mar 27, 2025 · Edited: Mar 27, 2025

I had the very same issue. It was solved by using PlateSolve 3.0. It’s a known issue with long focal lengths.

In my case, it happened with the EdgeHD 9.25 and Poseidon-M. After using PlateSolve 3 the issue was solved and never happened again.

Regards,

Alfredo

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Jochen Schambach

Mar 27, 2025

Sometimes I have the Same issues, it depends on Target Like m82.
focal length 1200, pixelsize 2.9

astronomy.net works well but very slow.

now im testing allskyplatesolver for blindsolve. It was easy to install.

https://www.astrogb.com/astrogb/All_Sky_Plate_Solver.html

With astap and platesolve3 in combination I have some other issues.

ScottF

Topic starter

Frequent contributor

Mar 27, 2025

Kyle Goodwin:
I have no idea which (if any) of these would apply to your situation, but to give you some things to rule out, here are the most common reasons an ASTAP solve fails:
1. The telescope isn't pointing roughly where it says it is. (The first solve on astrometry.net would sync it and subsequent solves would work.)
2. The image scale is incorrect. (You said the correct focal length is entered, but what about correct pixel size?)
3. The exposure is too short. (You said 10 seconds, that should be way longer than needed.)
4. FOV is small and has few stars. (Probably not a problem with D80 and 10s exposures to get fainter stars, but I'd also bin2)

Beyond those I'd need to see a sample of the image (and critically, the FITS headers from it) as well as your NINA/ASTAP config.

I'll see if I can post that information. However, in the plate solve window I can see my target off to the side so its definitely in the right area.

Kyle Goodwin

Mar 27, 2025

I use ASTAP at 2500mm of focal length with an APS-C sized sensor and the same star database without issue, so it should be possible to get this to work for you, too.

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ScottF

Topic starter

Frequent contributor

Mar 27, 2025

Kyle Goodwin:
I use ASTAP at 2500mm of focal length with an APS-C sized sensor and the same star database without issue, so it should be possible to get this to work for you, too.

That is good to hear, so my setup should work, there must be something I'm overlooking. I'll report back, after the next clear sky.

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Scott Badger

Mar 28, 2025

Kyle Goodwin:
I use ASTAP at 2500mm of focal length with an APS-C sized sensor and the same star database without issue, so it should be possible to get this to work for you, too.

Same for me except when seeing is bad. At about 4.5” it gets iffy and above 5.5” ASTAP rarely works. I’m not collecting usable data at that point, but no matter how bad the seeing, it’s still worth starting to image since the seeing may change, and sometimes quite rapidly.

Cheers,
Scott

Kyle Goodwin

Mar 28, 2025

Scott Badger:
Kyle Goodwin:
I use ASTAP at 2500mm of focal length with an APS-C sized sensor and the same star database without issue, so it should be possible to get this to work for you, too.

Same for me except when seeing is bad. At about 4.5” it gets iffy and above 5.5” ASTAP rarely works. I’m not collecting usable data at that point, but no matter how bad the seeing, it’s still worth starting to image since the seeing may change, and sometimes quite rapidly.

Cheers,
Scott

I just checked my image database and the worst seeing I've had over the past year was 5.5" according to the FWHM of captured data on my CDK. I haven't had any platesolve failures. Thankfully that sort of terrible seeing is very rare at my location. The best FWHM I've had is 1.1" and I generally cull anything above 2.5", or lower depending on the project. It could be that my location never gets quite bad enough to cause the problem you mention Scott. This is the time of year for it at my location, though. Seeing has been horrible for the past month, other than last night, which had good seeing for about an hour. I've already thrown out more than 12 hours of exposures on M63 which was "done" the night before last, but will actually require significantly more time as a result.

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ScottF

Topic starter

Frequent contributor

Mar 28, 2025

Kyle Goodwin:
Scott Badger:
Kyle Goodwin:
I use ASTAP at 2500mm of focal length with an APS-C sized sensor and the same star database without issue, so it should be possible to get this to work for you, too.

Same for me except when seeing is bad. At about 4.5” it gets iffy and above 5.5” ASTAP rarely works. I’m not collecting usable data at that point, but no matter how bad the seeing, it’s still worth starting to image since the seeing may change, and sometimes quite rapidly.

Cheers,
Scott

I just checked my image database and the worst seeing I've had over the past year was 5.5" according to the FWHM of captured data on my CDK. I haven't had any platesolve failures. Thankfully that sort of terrible seeing is very rare at my location. The best FWHM I've had is 1.1" and I generally cull anything above 2.5", or lower depending on the project. It could be that my location never gets quite bad enough to cause the problem you mention Scott. This is the time of year for it at my location, though. Seeing has been horrible for the past month, other than last night, which had good seeing for about an hour. I've already thrown out more than 12 hours of exposures on M63 which was "done" the night before last, but will actually require significantly more time as a result.

It might be seeing because the conditions have been horrific for months. Generally I shoot if it’s clear no matter what. I can’t be choosy about seeing conditions because clear nights are too rare. lol I do know the seeing was bad at the time.

Kyle Goodwin

Mar 29, 2025

I still shoot when the seeing is bad, but it depends on the target whether it'll get culled or not. On SNR most important targets (low surface brightness, usually) I'll keep more poor seeing subs than on detail most important targets (bright things usually) I'll cull more aggressively. A lot of times my refractor subs will be kept while the CDK subs are culled from the same night because of that kind of difference.

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Dan Conover

Mar 29, 2025

With my Edge 8 (no reducer) and Poseidon C I couldnt get ASTAP to solve at all. Seeing was good enough that it should have worked. Even bumped up exposure time too. I went over to Platesolve 3 and it worked every time however much slower than ASTAP. Using TPPA was easy with ASAP now its a bit of a pain with PS3.

AstroGinger

Mar 29, 2025

Sometimes a bad polar setting or forgot tracking during a plate solving will lead to tiny trails on the picture and then an ASTAP failure.

Tony Gondola

Frequent contributor

Mar 29, 2025

One thing that's clear from this thread is that ASTAP is a sensitive beast that really wants images that are just so. I never have a problem with it with normal configurations but if I push it with a narrow field from a small pixel camera, it's becomes very inconstant and in some star poor areas, will refuse to solve at all. Plate solve 3 is a lot more robust but even that will break down in star poor areas. Astronomy.net seems to just work no matter what you give it but lately it's been unusable, sometimes it will return a solution in a few min., sometimes it will take longer than I am willing to wait.

Plate solving is so central to how we operate these days and enough people have trouble with it that I really think it deserves a harder look and better solutions.

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Oskari Nikkinen

Mar 29, 2025

ASTAP is picky about tracking errors and star shapes. I'd say there is a chance your exposure time is too long, not too short. If you can, post an example of a sub that failed to solve and maybe we can find some clues in it.

My time using ASTAP has been almost without issue, currently with a 1160mm focal length f/4.83 scope. Half your focal length and twice the speed so not too helpful for your case, but i am using 3s exposures and so far i have only failed to platesolve on one target and in that case i just bumped up the exposure a bit.

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Tony Gondola

Frequent contributor

Mar 29, 2025

I'm currently using 20 sec. so I'll try to shorten that up and see what happens.

Observatório Astrográfico do Boqueirão

Mar 29, 2025

I friend of mine started to have the same problems regarding ASTAP and NINA.
Yesterday I've installed him the PS3 and I've changed the Blind solving for ASTAP with the D80 and D50 catalogs that he had and put some others in order to help it, and the PS3 was for primary imaging. I've changed a few settings for the platesolving also, but we could't test it yesterday.
Will do tomorrow.

One thing that I'm sratching my head is that he have his settings for location in NINA in decimals (like the Google Maps) insted of coordinates in degrees. Is that normal?

Best regards,

Cesar

Ian McIntyre

Mar 30, 2025

I have a difficult time with ASTAP at longer focal ratios, regardless of exposure time. Running native f/8 with my RC is challenging to slew and center. Filtering makes it nearly impossible to plate solve. I generally have no issue if I slap on the .65 reducer (bringing it to f/5). Try removing the LP filter and see if it works. I also sometimes tweak the gain up and occasionally that is successful at native FR.

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