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Observation by Mazin Younis: Need help to test my camera

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Mazin Younis


Mazin Younis


2021 Apr 24 - 04:11


2021 Apr 24 - 04:27



  • ZWO ASI 294MC-Pro

Need help to test my camera

About this image

Hi friends, 

I have been facing lots of issue (noise + artefacts) with my ZWO ASI294MC-Pro since I purchased it a year ago. I am not quite sure whether it's my telescope that is causing the issues (8" Quattro with Coma Corrector), or it's a fault in the camera itself.

My idea is to see if anyone is willing to (test) my camera on his/her Astrophotography telescope to compare results. If you happened to be in Manchester I can deliver the camera to you in person, otherwise can post it and cover the return postage.

Please let me know if you wish to help (and have experience in using CMOS cameras), as I have already lost many valuable clear skies :(

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David Swan
David Swan, 2021 Apr 24 - 08:19 UTC

Hi Mazin. Are you able to describe the noise and artefact problems in a little more detail?

Nick James
Nick James, 2021 Apr 24 - 10:26 UTC

Mazin - I have an ASI294MC-Pro and would be happy to help but I'm in Essex. I've never had any problems with mine. As David says can you provide a bit more info about what software you are using and what you are seeing. I guess you'll have swapped USB cables etc. Also is there any difference if you have the power supply to the cooler connected or not?

Mazin Younis
Mazin Younis, 2021 Apr 24 - 14:15 UTC

Hi David, Nick

Many thanks for your kind reply.

I get high level of pixel noise, RGB hot pixels, and many haloes and patches (circular and irregular). I always use Gain setting 120 @ -15C, calibrate with Darks and Flats, and have used DSS and PixInsight for stacking/processing. The problems I get are very unpredictable, can be quite bad or light.

I have (flocked) my telescope tube and made sure no stray light is getting through. Also checked that it's not condensation.

Here's a link to some of the photos after stacking and stretching:

David Swan
David Swan, 2021 Apr 24 - 19:58 UTC

Mazin. I've had a look at your images. I'm not sure I'm afraid. I can only think: refresh the  desiccant tabs, redo the calibration frames, check the cables (data and power) (as Nick has said). Scour the Cloudy Nights and Stargazers' Lounge fora for threads on problems with the ASI294MC Pro. Good luck!

Martina McGovern
Martina McGovern, 2021 Apr 24 - 23:31 UTC

Hi Mazin, I have a ASI294MC Pro & Celestron 8inch Edge HD. I have never experienced the issues/artefacts you are having - although I have only had this kit for about 1 year - still a Newbie to all things Astro. I too would offer to help with your experience i.e. if you send the 294MC Pro to me I could image with it.

I would say first though, the ZWO Facebook pages are very good, that is the members of the groups. There are many members (not ZWO "Company people") who use all things ZWO and have lots of experience - you could join the group/s and share your issues/images - they may be able to help you.

I have the ASIair pro (FYI, I think it is a amazing bit of kit ) so I joined the ASIAIR PRO USERS GROUP - although, you don't have to have the Air Pro to join the group :)
The members are extremely helpful.

Hope you can resolve the issue/s very soon.
Take care


Nick James
Nick James, 2021 Apr 25 - 08:29 UTC

These definitely look like calibration problems to me. The colour noise is hot pixels (depending on the colour filter of the Bayer matrix the hot pixel shows up as different coloured dots). The rest look like flat fielding problems. The question is why you are getting these. I'll contact you directly and get you to send me some of your raw frames and then will come back on the comments here when I've had a chance to look at them. This may be a camera problem but, more likely, it is something to do with technique.

Martina is right that you can probably get a lot of good advice on the ZWO FB site if you want to go there too. I'll have a look in parallel and, one way or another, I hope we'll find a solution.

Mazin Younis
Mazin Younis, 2021 Apr 26 - 03:00 UTC

Thanks Martina, Nick, for your valuable input into this matter.

Mark Phillips
Mark Phillips, 2021 Apr 27 - 08:27 UTC

I've just sent you an email Mazin but one possibility is cooling the camera too fast. I've had a similar (but slightly different) effect in the past with ice on the optical window causing strange effects including colour artefacts. My camera has a heated window but I now ensure it takes at least 5 minutes to get to -15C. Don't know how long your cam takes to get to working temperature?

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