We're using the STXL autoguider filterwheel, and have a problem we haven't experienced before. Using SkyX Pro, we're adjusting the autoguider pickoff mirror on the filterwheel, directing the scope at a uniform flatfield (Flatman). We're not getting a uniform AG image back; we tested the field by using our imaging camera and the field was fine, so the problem is somewhere in the AG's optical path. I've attached pics from the pickoff mirror being completely in and completely out. There's no noticeable difference, but the main concern is the obvious demarcation. We've successfully done this in the past. Please advise, thank you. Steve SPARQ Observatory
What's in the optical path? e.g. what scope and optical parameters, focuser, rotator, and how attached? Both images seem nearly identical, and look to be vignetted by a curved obstruction. Have you looked down the nose of the camera into the pickoff mirror? BTW FITS images are more useful, since we can measure values.
Thnx Colin. We're not seeing any obstruction in the light path to the primary imaging camera...I would think an obstruction would be present in both the AG chip and the main imaging chip (although I suppose there could be an obstruction between the pickoff mirror and the AG chip). Yes, I should have uploaded FITs. Next time. Steve
You could also open the FW8G-STXL filter wheel, and check that there is nothing in the light path to the guider. The pick off mirror directs light through a shutter and small 0.7x reducer lens before it gets to the CCD chip. It is possible that the shutter motor is not swinging the shutter properly, or there is something obstructing there. We've seen insects get in, especially with open-tube scopes.
