Jupiter and its Galillean Moons

[Stub Mandrel]

This image was compiled from around 200 subs taken with an astro-modded Canon 450D using a ~2x barlow with IR filter on a Skywatcher 150PL. the subs were divided 50/50 between exposed ideally for the planet and to show the moons. It is an interesting alignment as it has the three orbitally resonant moons arranged in a straight line. They can only ever line up two on one side, one on the other. This alignment is also unusual as the moons appear at distances reflecting their orbital distances with Io closest, then Europa, Ganymede and the non-resonant Callisto furthest out.

20 images with the moons were chosen and stacked manually in Corel Photopaint. The moons were under exposed to keep them as tight as possible, but this made stacking a challenge as they were quiet faint. It was quite difficult to isolate the moons from background noise in photoshop and both Ganymede and Callisto had to receive a bit of extra stretching stretching.

All frames were processed in PIPP, cropped to Jupiter, and the best stacked in AS!2, followed by wavelets in Registax - being aware that over processing would not suit this image.

The image of Jupiter was overlaid on the over-exposed Jupiter from the moons image and carefully centred.

After flattening the image very slight deconvolution was applied in Astra, then a smidgin of contrast enhancement, followed by a little noise reduction.

The colour balance has not been adjusted at all, except for slightly desaturating the moons.

[Dave In Vermont]

Nice 'string' you've captured, Neil! I like it!

Keep on,

Dave