Saturn at Opposition (Seeliger Effect?)

[Dave882]

Although not ideal conditions the last week with quite a a bit of cloud coverage the conditions were still quite stable and I was still able to get a few shots off for opposition. I thought it would be interesting to do a comparison with shots made on the 24th to see if I could record the Seeliger effect (temporary brightening of the rings at opposition). I did near-identical capture parameters and identical processing and assembled in GIMP.
To my eye I reckon I can see a small change but pretty hard to confirm as the seeing was a little better during opposition so will have had an effect.

c14 non edge
eq8
asi462mc (UV/IR)
ASICAP
AS!3
Registax6
5min captures
300gain
10ms

Thanks for dropping by!

[JA]

Hi David,

I see the 27/8/23 image as ever so slightly brighter, but definitely whiter / more bluish, but I'm not sure that one should expect much difference in brightness given that the images are only a few days apart. The slight difference in that context could also be due to other small changes such as seeing as you mentioned or transparency/faint cloud/solar changes, etc. Good stuff :thumbsup:

Best
JA

[Quark]

Nice work there Dave, clearly the seeing was better for your Aug 27th data than for the Aug 24th data.

Cheers
Trevor

[Dave882]

Cheers JA / Trevor. Yeah pretty hard to say if there’s a definitive difference when conditions differ. Be nice if I could just pre-order some consistently good seeing and then I could do a better comparison hey. But anyways happy to have had a clear patch to record the opposition anyways!!:)

[andyc]

Nice images Dave - yeah it seems to be tricky to see much difference over those three days. You've inspired me to do a similar comparison with a set of images over the past couple of weeks (I'm still processing them). The brightness difference is also not obvious across my 24th, 27th & 29th images (there, but slight). By the 6th September, the rings are visibly quite a bit darker.

It's a tricky comparison to do, because seeing, transparency, strength of sharpening, colour balance will all have some effect. But we both have a similar result I think for the 24th & 27th.