This image is a composite of Jupiter and its moon Io in the early morning of August 9th. We have been having some smoke from the wildfires in the Western U.S. the past several weeks, so transparency has been highly variable. In fact the location of peak intensity in the histogram drifted between 33% - 66% of saturation during the time I was recording data. I ended up having to use a longer exposure than typical for Jupiter because of this. However, seeing was good so I still was able to get a reasonable data set. For once, even the GRS was visible!

For these images, I used my C8 telescope with a 2x Barlow, QHY 5iii 178c camera, and an atmospheric dispersion corrector. The top image was created by stacking 4 separate videos obtained over 20 minutes and de-rotating them through WinJuPos. I stacked the best 40% of all frames (approximately 2400 frames total in the final image.) A second longer exposure was used to capture Io; the final image was a composite created using two different layers in Photoshop.

In addition, I was able to capture enough data (~3 hrs) to create a partial map. This was created using the Lambert cylindrical projection feature in WinJuPos. In principle, about 240 degrees of the surface should have been visible during that time, though much of that was close to the edge and highly distorted. Nevertheless, given that this was my first attempt at this, I was happy with how the map turned out.

I had thought that I was close to critical sampling with the native focal length of the C8 under these conditions with the 2.4 micron pixel size of the camera. However, based on the recommendation of two fellow contributors here on Astrobin, used a 2x Barlow lens this time, and it seems to have made a noticeable difference in resolution.

I include my acquisition details below. Not that someone would want to replicate what I did, but maybe someone else can learn from my mistakes!

Camera settings:
camera: QHY5III178C
ROI dimensions: 1468 x 1158 pixels
frames: 2030 (typical)
pixel depth: 8 bit/pixel
exp: 47.55ms               
fps: 21.16
gain: 25.00
exp: 47.55 ms

AutoStakkert! 3 settings:
Best 40% stacked
Align points: 49 (size 200), multi-scale