294MM pro subsampling

Vulpecula

Hello.

I have a 294MC pro + ED80 + 0.85x flattener with a resolution of 1.83 "at 1x1 binnig and I have had no subsampling problems. Now I have a 294MM with the same tube and flattener and on 2x2 binnig with the same resolution of 1.83 I have problems with I subsampling and the stars come out square.

I suppose this should be the same with the 294MC in 1x1 and the 294MM in 2x2?

Thanks.

Tech@ZWO

Hi,
You can use below link to calculate about this:
https://astronomy.tools/calculators/ccd_suitability

Vulpecula

@tech@zwo#51570
Hi, thank you very much for your interest and your response.

Yes, I have always used that tool.

What I mean by my question is that with the 294MC I do not have subsampling and with the 294MM I do, with the 2 cameras the same tube and flattener configuration..

Greetings

Tech@ZWO

Vulpecula
Are we talking about the comparison of same night? Because according to the calculator, the result is based on "Seeing".

noizeboy

Hi Vulpecula,

This is probably not that helpful, but I too have both a 294MC & a 294MM & binning them 1x1 & 2x2 respectively do not experience the issue that you do. Have you ever seen round stars from that unit or have they always been square? Have you experimented with the full range of binning settings?

Vulpecula

noizeboy Hi.
thanks for your reply. Not in 1x1 the stars are perfect.

WalterT

I believe the ED80 is 480mm, so with the reducer you’re operating at 408mm. I have an AT92 506mm with a Starizona Apex reducer so I’m effectively running at 329mm and I’m getting perfectly round stars with my 294MMP. I know it doesn’t answer your question but just to point out that not all 294MM’s have that issue, perhaps they sold you a lemon.

Vulpecula

WalterT Hi.
the ED80 is 600 and I am at a focal length of 521 mm. If I am thinking of the lemon.

Vulpecula

@tech@zwo#51654 Hi.
Different nights and with any filter although more with the SII. Never before had I had this problem with the 294MC

Tech@ZWO

Vulpecula
Can you try in ASIStudio and provide some fits for us to check? You can upload via Google Drive or Dropbox link.

Vulpecula

@tech@zwo#51719
Yes, of course. Now we have many clouds to clear I will try with ASIStudio. Thank you.