I'm trying to use ASTAP as a plate solver from within SharpCap. It fails because SharCap always sets the FOV parameter in ASTAP to "37.48" when it should really be "1.8"
When I run ASTAP stand-alone and open a saved SharpCap FITS image I can see the FOV value of 37.48 under "Alignment" and with that value the programs fails to solve. If I change that parameter to 1.8 it solve just fine.
I cannot change that parameter from within SharpCap and I cannot make it stick in ASTAP.
What can I do to make this work?
ASTAP as a plate solver fails
Re: ASTAP as a plate solver fails
Have you put in the correct focal length?
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Re: ASTAP as a plate solver fails
Hi,
yes, the field of view passed to the plate solving application comes from combining the pixel size of your camera and the focal length of the telescope (that either is set in SharpCap as shown above or fetched from ASCOM). It's most likely that the focal length is the issue (although SharpCap 4.0 could get a bit mixed up about pixel size when binning on some cameras - fixed in SharpCap 4.1).
The safest thing is to set 'Do not use' - that will let the plate solving application search all fields of view, slower but immune to 'wrong focal length' issues.
cheers,
Robin
yes, the field of view passed to the plate solving application comes from combining the pixel size of your camera and the focal length of the telescope (that either is set in SharpCap as shown above or fetched from ASCOM). It's most likely that the focal length is the issue (although SharpCap 4.0 could get a bit mixed up about pixel size when binning on some cameras - fixed in SharpCap 4.1).
The safest thing is to set 'Do not use' - that will let the plate solving application search all fields of view, slower but immune to 'wrong focal length' issues.
cheers,
Robin
Re: ASTAP as a plate solver fails
I had focal length set to "ASCOM"; I can force in the correct focal length, that might help. I've also found a command line switch I can set - "-fov 1.8". It's possible that SharpCap will over-write that too, but I'll try. Up here in western NY we won't get another clear night for over a week. I'll just have to wait to try it.
Thanks for the help.
Thanks for the help.
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Re: ASTAP as a plate solver fails
Hi,
OK, the ASCOM mount driver may have had the correct focal length, but only if you had previously configured it in the settings for that driver. If you hadn't done that then the focal length would quite likely have been a default and therefore wrong. From the fact that it was trying a 37 degree FOV, it sounds like the focal length was coming back as very short.
SharpCap will always send its calculated FOV to Astap if it has a focal length available. If you want to use -fov on the additional command line options then you will need to set 'do not use' in the settings to avoid this, making your -fov the only one.
cheers,
Robin
OK, the ASCOM mount driver may have had the correct focal length, but only if you had previously configured it in the settings for that driver. If you hadn't done that then the focal length would quite likely have been a default and therefore wrong. From the fact that it was trying a 37 degree FOV, it sounds like the focal length was coming back as very short.
SharpCap will always send its calculated FOV to Astap if it has a focal length available. If you want to use -fov on the additional command line options then you will need to set 'do not use' in the settings to avoid this, making your -fov the only one.
cheers,
Robin