ASTAP FoV persistent setting

[Clouzot]

Han,

I'm using ASTAP both for offline platesolving (from FITS or PNG originating from different sources) and from within Sharpcap.

It works blazingly fast...most of the time. And when it fails, it's often (always, to be honest) that ASTAP has previously manually solved an image with a given FoV, and has set itself to this FoV from then on. That FoV setting is even persistent so it never goes back to "Auto". Every command-line call will use that detected FoV as well.

I see the advantage in doing so (subsequent platesolves are faster), but for people that routinely have captures with different focal lengths or sensors, that may be an issue. Would the command-line options allow Sharpcap to set the FoV to Auto (if so, that's something that should be changed in Sharpcap)?

Thanks again for your software (including HNSKY, which is my weapon of choice as well)

[han.k]

Hello Couzot,

Yes the commandline will override the FOV (image height) setting. ASTAP will use the folliwng FOV as available:

1) Command line value (the -fov parameter, zero is auto)
2) From FITS header
3) Last good value.

So the command

"c:\program files\astap\astap.exe" -f fitsfile.fits -fov 0

will ASTAP in auto FOV mode.

This command will force a FOV of 1.3 degrees:

"c:\program files\astap\astap.exe" -f fitsfile.fits -fov 1.3

What I remember from the discusion with Robin is that SharpCap will first try to solve the image and if no solution is found SharpCap executes the auto FOV mode using -fov 0 I personally don't work with ShapCap but is that not the case? If not something has to be modified in SharpCap. You could ask at the SharpCap forum,

Clear skies, Han

[Clouzot]

Thanks Han,

I don't really know how Sharcap forms the command line that invokes ASTAP (it may be buried in some log), but what I saw was the following :
* using my tiny refractor (240mm focal length) and 183MC (the combination should yield something like 2° x 4° of FoV), started capturing frames

• instructed Sharpcap to platesolve with prior knowledge of the mount position

• I could briefly see a popup stating that ASTAP had detected X stars and that it was trying to solve around the mount's assumed coordinates, for a FoV of 0.59°, all of which with a 180° angle that I assume is the spiral search range around the mount position.

• I waited a bit (say, 5 minutes) and Sharpcap ultimately told me that platesolving had failed

• I then opened ASTAP, went to the Stacking/Alignment tab, and saw that the FoV was indeed set to 0.59°. It had been the case since the last platesolve I manually did for an image from my 9' SCT

• I set it back to Auto, closed ASTAP, and relaunched the platesolve. It then succeeded almost immediately, and so did the following platesolves.

So, somehow, ASTAP didn't get the correct FoV reset command from Sharpcap, and I suspect it doesn't form the command line using the -fov 0option.

[han.k]

I will test it with the latest SharpCap version.

[han.k]

Hello Clouzet,

I have tested it with the latest Sharpcap. If the solve is unsuccesfull it will do a search with auto FOV. It also fixed the search area to 15 degrees, so it goes pretty quick.

Maybe you using an older version of ASTAP. Around april I have changed to command line to make auto FOV in the commandline possible with SharpCap. Can you try it with the latest ASTAP version?

Clear skies, Han

[Clouzot]

Thanks Han,
I'm pretty sure I'm using a recent ASTAP version (at least there's no more "auto correct colors" in the menu, so it should be a June-ish build) [by the way I'm missing that feature ;) ]

If weather cooperates tonight, I'll update everything and will report here.

[han.k]

I see, the " auto correct colour" menu was removed by a typing accident. I will return it. It is still available in the "pixel math 1" tab.