What is wrong with my optical train?

Recheck your collimation. It's very critical to a sharp image but even if it's ok your at the mercy of the weather. Try and image on only the steadiest nights.

I'm not that experienced in planetary imaging but I took a seminar on that a few years ago and here's what I remember:  Take several minutes of video; this will allow you to select the best frames as seeing changes constantly when imaging planets.   When you have your best frames selected, use Autostakkert or Sharpcap to process your images. It's in the processing that you can bring out the sharpness and detail of Jupiter and Saturn.   Also,  I believe Adam Block has a series of tutorials on planetary imaging that are very useful.  Hope this helps.

CS
Patrick

Alan Hancox:
Recheck your collimation. It's very critical to a sharp image but even if it's ok your at the mercy of the weather. Try and image on only the steadiest nights.

maybe I have never had good seeing yet - but last days have been pretty good, and ai die notice improvements in quality. 

but could seeing or collimation shape rhe moons into croissants?!

Your odd looking moons suggest you are not in fact well collimated because even in bad seeing they should be round and not crooked like here. Id say there is a fair chance you are way off ideal collimation.

Just so you know an ADC is not strictly necessary for sharp planetary images at 30 degrees of elevation, like pictured below from one of my last years images taken with an 8'' f/4.4 newtonian barlowed to around f/12 if i recall correctly (and an ASI678MC). Taken in september 2022 from 60N when Jupiter was right around 30 degrees in elevation, and no ADC was used. Although an ADC would certainly have improved the image at this elevation i think you will still agree that the lack of an ADC is not holding back the image too much to be any kind of main concern.


But also just want to point out that nights with clarity like the above image are very rare with the results with my scope usually looking something like below, which was imaged on september of this year with a much better elevation of above 40 degrees. Still softer because seeing was not so good this time.


So everything could be right, but the skies will just not give, but i think your setup has some work to do.

I'd say look into collimation once more, and this time maybe do that with the planetary imaging train itself on a slightly defocused star.

andrea tasselli:

Arny:
But could that explain croissant like moon shapes?!

It could, if improperly set up. Or your scope is massively out of collimation. Or both. I'm slightly north of you (53.2N) and I'm pretty sure that the time of imaging Jupiter is pretty much past this season. Besides, It has been cloudy for the past four weeks...

Thanks, Andrea - your experience underlined by your great planetary images speak for the fact its lot my lattitude :-)

As there is consent in the comments on my collimation being the reason I‘ll tackle this. In fact I have checked out of focus only - will try in focus with high power piece. Thanks!

But when you say Jupiter season is over, ai was surprised, as it will keep rising higher and earlier each night until