My guide stars are looking funny with a long tail. See attached. I tried to carefully focus on the filter wheel and still get this tail. It screws up the accuracy of the autoguiding in the X direction. I did not have this until recently, though have seen such stars in the past long ago. Seems to be the bright ones. Any suggestions as it is screwing up the guiding????? Suggestions from cloudy night: U r using an OAG I presume. Its probably that the OAG field is close to the limits of the FOV and u r getting curvature. My response: Yes, the STT 8300M with the filter wheel has a prism in front of the filter wheel which pulls off the OAG image. It seems that these images are in the periphery of the autoguider images. I think perhaps there are settings in Maxin where I can maybe select a centralized subfield or bin the stars more. I think I am using 2x2 and maybe 3x3 will squeeze the stars down. Problem is what we used to call aliasing/anti-aliasing in graphics programming. You can see the individual pixels sorta flip from bright to dark along the edge of these stars... I also need to check the prism tilt. There is a control for that too.
As I mentioned in the other thread, distorted stars are common off-axis and shouldn't impact guider performance.
jerryyyyy, I use a Tak fsq106 and my guide stars are a bit worse. It don't really bother me though, since my guiding works just fine...
Yes, mine works fine now too. I have been implementing automated focusing and that actually has improved the stars. It is a bit tricky since my SBIG has an off axis prism and who knows what that is going to do.
I am using a stepper motor for auto focusing. I have the FW8G-STT self-guiding filter wheel. My Taq 106 has an image diam of 88mm. The guide chip is no where near the limit of the fov, so that can not be the reason in my case. I have tried to refocus and move the guide mirror in different positions, but still get the star tails. This is more "fyi", since it's not a problem for me...
