SharpCap Forums

Guys,

just wanted to mention a small quirk when using ASTAP for platesolving in SharpCap.

One of the main issues that often prevent ASTAP from solving is its FoV setting. It's well hidden in the so-called "stack window" under the Alignment tab.
Before even trying to launch a platesolve from Sharpcap, open ASTAP and make sure it's really set to Auto, then close ASTAP if you want. Then you'll be sure that ASTAP really tries all kinds of FoVs (from 10° to 0.4°) before giving up.

Problem is: if you manually solve something within ASTAP itself (by opening a FITS or a PNG, for instance), the detected FoV is set...and saved as a setting, for some reason. Next time you try and platesolve from Sharpcap, ASTAP will only try that FoV. That shouldn't be an issue if you always use the same telescope, sensor and focal length. But if, like me, you often switch from a small refractor to a barlowed SCT (a 240 to 4700mm range), or routinely platesolve images from friends, you'll probably run into problems at some point.

@Robin, would there be a way to have ASTAP reset its FoV to Auto when Sharpcap is calling it? Or is it something I should ask Han, ASTAP's author?

Thanks for the tip!
-Chris

Hi,

SharpCap already does this when you use the plate solving button from the mount controls – it will first run Astap in a mode where it will use the previously saved field-of-view then if that fails it will retry passing the '-fov 0' parameter which tells Astap to use the auto FOV setting.

This doesn't apply if you are using the blind plate solving option from the tools menu on the assumption that running auto field-of-view across the whole sky would be too slow.

Cheers, Robin

Related to FOV setting for ASTAP, when I run Plate Solve, it takes 7 minutes.
Running standalone it take less than 7s for the same image.
The image FOV is 0.51º. I'm using G18.
Image exposure is 30s with a gain of 180 for the QHY128C. Plenty of stars.
The search view setting in ASTAP for standalone is 0.51º.
But the search view setting when running Plate Solve in Sharpcap appears to be 180º.
No wonder it takes so long.
If I use Astrotortilla to plate solve, it takes 1m 20s.
What haven't I set up right?
And why can't I find anything in the Sharpcap manual on plate solving?
I'm using the instructions that came with ASTAP.

Hi,

If you use the plate solving button in the telescope control area then the field of search is 15° around the current pointing position of the telescope – see https://docs.sharpcap.co.uk/3.2/#Mount%20Control

The plate solving menu item is designed to be used by those who haven't connected their mount to SharpCap – in those cases SharpCap has no idea about the initial pointing position of the telescope, so uses a field of search of 180° to search the whole sky. https://docs.sharpcap.co.uk/3.2/#Plate%20Solve

Cheers, Robin