Hi,
I was trying the SEP multistar guiding algorithm last night -to much delight I should say (thanks for a great tool)- when I stumbled on a small problem potentially affecting any guiding based on automatically selecting stars:
My setup has a fixed guidescope pointing in the same direction of the main scope and this means the target is partially visible in the guide frame. When pointing at a globular cluster the star selection algorithm just goes crazy....
Is there a way to tell the guide module to avoid certain regions of the guide camera frame?
Or to select stars only from certain areas?
That would be a good option to have also in the case there are areas affected by excessive aberrations or permanent defects...
AWay from the globular, the SEP multistar performed amazingly well, at times achieving RMS below 0.4 arcsec (HEQ5, 60/700mm guidescope, ASI120mm camera, 2 sec exposures, 0.7x guiding rate).
you're right, having an annulus like in the focus TAB would be a welcome addition to the guiding TAB. In the meantime you might want to chose the guide star by hand. If I recall correctly SEP-multistar chooses its guide star automatically (I could be wrong here) so you'd have to go with a different guiding algorithm like SEP.
Could you please upload somewhere around 10 images similar to your guide frame, from your guide camera, with the same exposure/gain as used in guiding? Also a screenshot of the StellarSolver profile parameters you're using for guiding and whatever parameters you're using for guiding, eg binning, etc
Of course Hy, I'll take them as soon as I get another clear night (unfortunately, most likely not in the next 7 days according to the local weather forecast).
I should add more specifics: the situation presented itself during guiding calibration. The central area of the globular was in the guide frame and the auto star selection algorithm tended to pick a bright area within it as guide star. This inevitably resulted in a "guide star lost" error during calibration. So, in practice, the guiding could not really start in that scenario.
I guess I could try calibrating a bit off-target and then moving back to it to see how having the globular in the guide frame affects the actual guiding...
I think there's no way to save guide images right now, so what I was suggesting was to use the capture module, but select the guide camera as your camera, point to the same view you had for the guider, eg with the cluster as part of the frame, and set the exposure and gain like you had for guiding, and capture 10, or why not 20, images in a sequence.
These images are not binned but I normally run the guide camera binned 2x2 (less noise helps my guiding more than higher angular resolution).
Hope they will be of help.