Saturn and Jupiter

My objective for this session was to image Saturn and Jupiter while trying to autoguide with FireCapture’s orgainic autoguiding capability.

Even though I had a good polar alignment last night, I elected to check it with PoleMaster so that I could tweak it if needed, because having a good polar alignment makes planetary imaging easier if I am manually guiding. It turns out that it needed a fairly significant adjustment, about as much as it needed after aligning with the alignment scope. Not trusting that result, I ran through the Polemaster routine again, and it needed a small tweak in the same direction as the previous adjustment. Not sure why such a big adjustment was needed.

My first slew was to Deneb, where I first did a star alignment. This is not something that I normally do in my planetary work flow, but why not since I was already on a known star. I also worked on my collimation there. I found that it was off just a little, and I estimated that better seeing and having the 2.5x PowerMate helped reveal the mis-collimation that I could not see before. I elected to take the dew shield of to correct it and found that removing was not that big of a deal.

From there I slewed to Saturn, which I could see through the trees. I was working with you for about 20 minutes while waiting for it to come out of the trees. When I came back, I found that I had left the dew shield off and the corrector plate was starting to collect dew. I put the dew shield back on and turned up the heat. What I learned from this is that removing and installing the dew shield is not that big of a deal. Thinking that it was big deal had been a barrier to learning how to collimate in the first place.

As a result of this exercise, I have decided to incorporate collimation into every session because good collimation is important, and because I will get better at it with practice. My streamlined workflow will be to leave the dew shield off when setting up. After polar aligning, I’ll slew to a bright star to get a star alignment, check/adjust collimation, do an initial focus, and then install the dew shield.

I elected to manually guide during my Saturn and Jupiter capture runs, because I wanted to rely upon what I already know how to do (manual guiding) instead of putting my captures at risk while trying to learn something new (Firecapture autoguiding). It turns out that the drift last night was even less than the night before, so if I can keep my polar alignments this accurate, manual guiding will always be a reasonable alternative if for any reason I cannot autoguide.

In spite of having to dodge passing clouds that were affecting my histogram in mid run, I think that I got some pretty good data on Saturn and Jupiter. Seeing was better than last night, I would say a 4-5/10 on the Pickering Scale. There were a couple of episodes of worse seeing, but on average it was not as good as it was the last time that you were here. I think that I managed to get five LRGB sets on both planets. I’ll stack the channels, color combine each set into a stand alone RGB image, and derotate them in WinJUPOS starting today. I still have the night prior’s data to process as well.

It was neat watching IO being occulted by Jupiter during one of the capture runs last night. Now that my captures and processing have improved, I hope to catch one of the moons transiting the face of Jupiter.

The results with autoguiding were mixed. I was able to connect to the mount from FireCapture via ASCOM with ease. I could see the mount issuing commands. Most were in the direction of the up and right arrows, but there were occasional nudges to the down direction. This might be why Jupiter drifted downward, and thinking about it this morning, maybe the drift was a little faster than when I was manually guiding. Maybe the guide pulses were too long, maybe the guide pulse durations need to be customized for the amount of drift that is occurring. I need to read more and pay closer attention the next time that I try it.

Saturn - 2021-09-04 02:30 UTC
Jupiter - 2021-09-04 0323 UTC

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