62161Stars focusing into lines
- May 1, 2008I need some help in figuring out a problem I am having getting a new
camera setup in my scope. I am using an 8" reflector that is 1000mm
with a DSI III pro.
I have the DSI attached to a CFW8a filter wheel and use a MPCC coma
corrector in the nosepiece.
With this setup I get stars that look like little lines when it is
just outside of focus. Images are producing stars that are very
I can rule out guiding as a problem. I have used this my same scope
setup and mount with a different camera and no guiding issues. The
star problem shows up in images as fast as .2 seconds.
I can also rule out colimation. The scope is well colimated and my
DSLR in the same scope produces perfect stars.
One thing I notice is when I check the focus on a bright star the
diffraction spikes on one side dont converge. Normally when I get
perfect focus all 4 spikes are perfect lines. With this camera setup
I get 2 spikes as nice lines and 2 spikes split and blurred.
Ok so now where do I look for the issue? My thought is this is some
kind of tilt problem and I was wondering if the symptons match that
My next step was to remove the CFW8 from the mix and try the camera
straight through and if the problem lies with the camera itself.
Any tips or tricks that might help me figure this one out?
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