Beginner's Woes

[DaveAus]

Sorry but I'm absolutely new to CCD imaging and today I unpacked my new 383L+ camera. Attached is a snapshot taken through my Vixen R200SS 8" Newt and a Quantum 7 slot 1.25" filter wheel. Clearly I have a vignetting problem as shown by the rounded shadow in the bottom-right corner. It looks like the filter is not centered on the camera's axis. This may necessitate my having to replace the Quantum filter wheel with an Atik model. But what puzzles me is the dark area in the top-left corner. I do not understand what causes it. If I did I would know how to tackle the problem. Can anyone explain it to me? Thanks.

[DaveAus]

Further to my original posting I attach an image taken using the camera's 2" barrel and no filter wheel. The image is of some distant trees although it is well out of focus due not having enough back focus with just the 2" barrel. Understandably no vignetting is evident but the image does show that the same dark shadow covers the top-left corner of the frame as was evident in the image attached to my original posting. What can be causing it? Is there a defect in the camera? Any advice will be welcomed. 

[clouds2nite]

You need to use spacers to get the correct back focus, are you trying to use it in daylight  or  night.

Camera does not have short enough exposure times for daylight images.  I set up my  camera at night looking at distant lights to get the focus using 1 second exposures.

Regards,

John

[DaveAus]

Thanks for your reply John. It is really appreciated.

I'm OK with with the focussing situation. I only used the 2" barrel to avoid the vignetting problem I currently have when using the filter wheel. I won't be using the 2"barrel under normal conditions and I can get focus when using the filter wheel.

Regarding the problem shadow, I now believe that it was caused by the shutter and that I was using too short an exposure setting. Doh! No excuses - I should have paid more attention to the instruction manual.

Now if only I can solve the disappearing Exposure Settings window problem (see separate post in the Everything Else section) I'll be off and running.