StarTools

What do you think may be due to this curious shape of the image after using Autodev?

It could be walking noise , what was acquisition details / setup are you guiding , dithering, taking flats , darks etc .

Also autodev can be quite ugly until crop of artifacts etc. has been done

Those are the paramethers:

Evoguide 50 ED
Coma corrector Starizona EVOFF
Altair 294C ( -10ºC)
Celestron Evolution
Darks+ Flats ( Histog. 50%)
Sharpcap

56x15" stack

No guiding

This is a screeshot of Autodev:

That's a fork mount and not an equatorial, isn't it?

In which case what you are seeing may be walking noise combined with field rotation.

Not sure how to fix that - a wedge, possibly and then guiding. Or it may be that you need to change the way you obtain and stack your darks?

almcl wrote:you are seeing may be walking noise combined with field rotation.

+1

This may be ameliorated (or even completely resolved) by dithering aggressively between frames.

Many thanks to all for your advice.

I'll do what you told me

elpajare wrote: Evoguide 50 ED
Coma corrector Starizona EVOFF

How are you getting on with the 50ED and that EVOFF?
Is it working well for you or is this your first image with them?

This equipment belongs to a friend who asked me for advice, it is not the one I use.

He tells me he is happy, but having seen what you say, I have advised him to change it

I use a TSOptics C8 + IMX 294C and these things do not happen to me, my Autodev are clean

thank you for replying.
please could you update this thread if your friend fixes the problem and what the fix was?
I have the same telescope and am considering that field flatterer.