Equipment

Imaging telescope / lens Celestron Schmidt-Cassegrain (SCT) 8"/2032 mm 8SE
Imaging camera ZWO Optical ASI183mm Pro (CMOS)
Mount Equatorial Sky-Watcher HEQ5 Pro
Guiding telescope / lens Celestron Schmidt-Cassegrain (SCT) 8"/2032 mm 8SE
Guiding camera ZWO Optical ASI120MM Mini (mono) (CMOS)
Filters ZWO Optical Luminance (UV/IR block) 1.25"ZWO Optical Red 1.25" 90%ZWO Optical Green 1.25" 90%ZWO Optical Blue 1.25" 90%
Accessories Off-axis guider ZWO OpticalFocal reducer Celestron 0.63xFilter wheel ZWO Optical 1.25"Automatic focuser JMI MotoFocus+
Processed with Siril 0.99.6, GIMP (GNU Image Manipulation Program) 2.10.20 (revision 1), PHD Guiding (Stark Labs)


Frames / Subs

Lights (filter Luminance) 30 x 30 sec
Lights (filter Red) 30 x 30 sec
Lights (filter Green) 30 x 30 sec
Lights (filter Black) 30 x 30 sec
Darks 25 x 10 sec
Flats 50 x 0.01 sec
Bias 60 x 0.001 sec
Total lights integration time 1:00 hours


Acquisition

Date Sat Nov 14th 2020
Seeing 3 / 5
Transparency 3 / 5
Camera Sensor Temperature -10.0 ºC
Binning 2x2
Gain 200

Have you considered using a reducer/ flattener? They're not expensive and reduce the effective focal length to 1280 mm with an aperture ratio of 6.3.
With your 2.4 micron pixel dimensions, you're very over-sampled, especially considering the mount and seeing.

Another piece of advice: isolate your SCT tube. Only the tube. This reduces tube currents dramatically!

Hi Bart

Thank you for the advice. I already use f/6.3 reducer all the time. This picture is with the reducer.

About the SCT tube isolation, what do you mean by that?


Thank you
Mohamed

Ah ok!

I mean to thermally isolate the tube, in order to reduce 'seeing', but seeing that's generated within the OTA itself.

I don't know of a topic on an international forum. On the Dutch forum there are some topics about it, describing excellent results!
So I recently did mine, but hadn't had a clear night yet.

(Edit: here is the link, maybe use google translate: www.astroforum.nl/threads/koeling-c11.1467548/ )

Thought you might like to know that with negligable investment, you can get better quality images