Collimating a Starlight Express SXVR-M25C

The newer cameras have an o-ring between the camera body and the tip/tilt plate, this o-ring prevents light leaks and more importantly during alignment acts like a spring.

The black screws set the adjustment once you are done, think of them as a jam nut. The silver screws are used to make the actual adjustments.

If your camera has the o-ring when you begin you will back out the black set screws so they are out of the way and only use the silver screws. Remember the goal is to keep the o-ring compressed so that it can act like a spring and prevents light from leaking in.

I used CCDInspector to assist me in the alignment of my chip. It took me a while to figure it out and get it right. Here is some information that I learned from the process. This should save you some time and frustration.

CCDInspector provides information about errors in "tilt", these are specified in axis (X & Y) and + or -. It gathers this information by measuring the FWHM across the entire image.

From performing my alignment I learned that if the error is in - (negative numbers) you need to unscrew the appropriate silver screw. If the error is + (positive numbers) you need to screw in the correct silver screw.

So to summarize:

X = Left/Right
Y = Up/Down
- error = unscrew
+ error = screw in

Be sure to have the best focus possible, refocus often if necessary. Also be certain that the tilt you are seeing isn't being caused by something else in the optical train. Take 30 second subs and take at least three between adjustments to make sure you are making actual corrections. Try a part of the sky with a dense star field, like Cygnus for example.