Jupiter Io Shadow transit, 1st Feb 2024

[lukebl]

Here's a quick capture from this evening showing Jupiter's moon Io and its shadow, along with the Great Red Spot (nowadays it's more like the shrinking beige spot!) appearing lower left.

250mm f/4.8 Newtonian, 5x Televue Powermate, ZWO ASI120mc cam. c 5000 frames @ c.50 fps, 17ms exposures.

I'm not happy at all with the image.

For some reason, when processed in Autostakkert the image shows some horrible artifacts making it look like it's made with oil brush strokes.  I've managed to reduce it in Photoshop but at the cost of loss of definition. I used the same setup with previous apparitions of Jupiter and Mars and got excellent results, so I've no idea what's gone wrong. Any suggestions as to what's gone wrong would be welcome. I'm using the latest version of Autostakkert and capture with Firecapture..

This is an image before softening in Photoshop:

Here's a detail showing the artifacts:

[John_D]

Great composition but I see what you mean about the artifacts. Have you tried pre-processing with PIPP before using Autostakkert? I've no idea if it would make any difference but it's free to try and reasonably easy to use

[Kon]

Did you try with the older as!3?  It seems to be something with the box size at the neb, you have a square artefact. You also seem to have a lot of noise from wavelets too.

[lukebl]

3 hours ago, Kon said:

Did you try with the older as!3?  It seems to be something with the box size at the neb, you have a square artefact. You also seem to have a lot of noise from wavelets too.

Thanks for the input.

I had a go at capturing Jupiter last night using Sharpcap instead of Firecapture. Conditions were pretty poor with bad seeing and the results weren’t good. However, I seemed to be able to get shorter exposures and a higher frame rate with Sharpcap, and the initial results don’t seem to show those artefacts. 

So it might just be the capture software that’s a problem. I’ll try again when conditions are good.

[John_D]

You could also try the free ASI Studio capture software. It's quite basic but I've used it successfully on a low powered laptop where other software gave me trouble.

[bosun21]

Just looks like excessive noise from too much wavelet sharpening to me. I also use Sharpcap and AS4. The only time I've seen this appearing is when I increased the wavelets far too much.