Plate solving SGP & APT

[Imme]

They talk about 'Mysteries of the universe'.........my mysteries start with plate solving!

I'm after some advice......

I'm recently purchased a second hand QHY 8 Pro and am using it as my imaging camera with APT. Problem is it wont plate solve!

Strange thing is if I load the exact same image (taken with the QHY) that APT is trying to plate solve into SGP then it solves in a reasonable time.

Problem with APT plate solver you say......well, I can take a pic with the Canon DSLR and it plate solves no problem in APT

APT settings.....yep, they are changed to suit the QHY 8.

I'm absolutely stumped on this one!

Could it be I'm not collecting enough data for APT to be able to plate solve (10 second image) but for some reason SGP uses the caught data more efficiently (does it use a stretched image and APT doesn't?)

...any ideas?

[Camelopardalis]

Both programs use the same plate solving backend. They both write out a raw image that the solver analyses.

Both are pretty sensitive to having the correct telescope focal length and pixel size entered in their respective settings.

One thing to look at when PlateSolve2 is running is to look for the number of extracted stars...too many can be bad as is too few.

What exposure time are you using for plate solving in SGP? Whatever it is, I suggest you try that for APT too ;)

[Imme]

Thanks Dunk......that's the thing.

The image I'm solving is exactly the same picture.......Settings are the same in both programs for pixel size and telescope details and as you say, both programs use the same backend loaded on the same computer!

I just don't get it!

[Camelopardalis]

While you have the PlateSolve2 window open, check the Keep Open box and then in PS2’s View menu select Parameters and see if there are any differences there. Other than that, I’m stumped :shrug:

FWIW the only problems I’ve had with PS2 have been where there are too many or too few stars, and when I’ve got the focal length wrong ;) other than that, it works well for me in both programs (and I do use both regularly)

If the parameters are different, ping Ivo a message...he’s pretty responsive and might be able to shed some light on it.

[Imme]

Cheers Dunk

[billdan]

For platesolve2 to work it needs a hint as to where you are pointing. Maybe SGP is passing that RA/DEC address to platesolve2 but APT isn't doing it.

EDIT: I just read that APT platesolved OK with your DSLR, so I'm stumped.

[Camelopardalis]

One thought...does APT know the pixel size and chip dimensions? With my ZWO it picks this up from ASCOM, but worth looking in Tools and see what it’s reporting.