Hi. I’m currently using a c9.25 xlt with an Atik 383L mono camera andt Atik filterwheel. I use a celestron 0,63x reducer. Also I am using a moonlite focusmotor.
I connect the camera to the reducer using different extension tubes to aquire the desired 105mm (or so) distance from reducer to sensor. Then I slide this set up into the focuser. The reducer will then be placed quite far behind the primary focus at the back end of the telscope.
Using this set up produces different kinds of artifacts in stacked images. Se attached screen shot.
(Placing the reducer inside the focuser increases the distance from reducer to sensor to about 120mm and produces very destorted stars in the outer part of the image and is not an improvement of this set up.)
Has ayone experienced similar problems with artifacts using this type of scope and reducer? If so, do you have a solution to my problem? Will it help to screw the reducer directly to the scope (and getting rid of the focuser)? (and maybe use a focus cube on the main focusing knob to maintain fine focusing).
(My hypothesis is: the reducer is too far behind the primary focus and/or the primary mirror shifts when I produce flats using my flat panel by pointing the telescope vertically - and thus in another direction than the one i imaged in).📷 image.png
Artifacts in stacked images with C9.25 XLT and reducer setup
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Thats over correcting flats i reckon… that would be my first check. Try getting some flats with a lower average adu counts and some with a slightly higher average adu counts and re-calibrate and stack the data.