Finding Himalia - 2022 Edition

Last year I decided to see if I could image Jupiter's Moon Himalia and I blogged about it right here. I ended that blog post by saying that I would try to find it again in 2022. Well, it is 2022 and the time is right, but fading fast.

At magnitude 14.6 Himalia is not especially faint. Targets of that brightness are easy to catch with a Unistellar eVscope. The problem is that it is close to Jupiter in the sky and that Jupiter 17.4 magnitudes brighter than this moon! That means that Jupiter is more than nine million times brighter than Himalia!

To diminish the glare from Jupiter it is best to observe Himalia when our view of its orbit is such that it is both far from Jupiter and when Jupiter is close to Earth, which makes the moon's orbit look larger in the sky. Currently Himala's orbit is about 2 degrees across (4x the diameter of the full Moon).

Himalia's orbit around Jupiter (image from SkySafari Pro).

The peak of both these factors is right now (actually, it was just over a week ago) placing Himalia around 53 arc minutes (almost 1 degree) from Jupiter in the sky.

This year I was observing with an eVscope2. I also had an Optolong L-Pro filter on the telescope which I was hoping might diminish some of Jupiter's intense glare.

I looked for this little moon on August 26 & 27 2022. Thankfully, the glare from Jupiter did not look as bad as it did last when I tried this last year (I think that the filter helped), but the glare still makes the view different from one image to the next. Here are the two frames blinked:

Yeah, spotting it here is difficult, but you might notice that there is a galaxy (NGC 132) to the right of center. Himalia is beneath it in one frame (taken August 26) and to the right of it in the next. 

It is much easier to see in this view that has been cropped, zoomed and annotated:

A nice clean detection!

It turns out that Jupiter's moon Elara was likely in the same field of view of my full-frame images, but at magnitude 16.2 it is quite a bit fainter and I'm not convinced that I caught it. 

While I was pointed near Jupiter I decided to go ahead and look at Jupiter too and was pleased to see that the Great Red Spot was visible. Now the eVscope2 has a really wide field of view and Jupiter looks pretty tiny, but with cropping and upscalling you can easily see its belts, zones and even the Great Red Spot.

Jupiter with the Great Red Spot

I've got some other faint moons to try. I will report back here if I have any success.