Not expecting decent weather for a couple more days, I took the camera off of the scope yesterday morning and covered it. A HAL member’s request during the day for someone to open Alpha Ridge for an impromptu star party prompted me to take another look at the weather. Finding average transparency and above average seeing until 0100, I ended up taking the cover back off of the scope and putting the camera back on after dinner. Also, I was expecting heavy dew all night, but it didn’t turn out that way. One of my primary objectives in this session was to try out the UV/IR cut filter.
Since I had bumped the mount pretty hard while covering it earlier in the day, my first task after dark was to re-establish polar alignment. I was not expecting to see Polaris in the Polemaster display when I started the app at 2020, but it was already there. This is an hour sooner than I was polar aligning at the solstice.
Saturn was out of the trees first, so I worked on it from 2230 to 2330. My first two runs were L only, and overexposed to reveal a couple of satellites, then I decided to wait a while Saturn ascended to 35 degrees elevation. I shot five RGB runs at 45s/filter, 9.9s exposure, and 420 gain for a 60% histogram. Seeing seemed pretty good, but focus was difficult as Saturn’s features are not very contrasty. Because if this, I was not able to determine much about the UV/IR cut filter while I was at the scope. The RH was 35% when I came inside from this part of the session.
The tabletop, which is usually the first thing to dew up was still dry, so I was not able to tell whether the dew shield/heater were making a difference. I did notice, that the outside of the shield does not get as warm as the outside of the standalone strap. I take this to mean that the shield helps to keep the energy on the telescope instead of letting it radiate away. I am hopeful that the dew shield solves the problem.
Next was Jupiter, which I went back out to the scope to work on at about 0005, and had to wait a few minutes for it to clear the trees. I shot five RGB runs at 30s/filter. 9.9s exposure and 365 gain for a 70% histogram. The seeing had deteriorated from when I had shot Jupiter, but there was pretty nice contrast, especially in G and B. The image in the display had a different quality that was hard to describe, but I think this might be attributable to the UV/IR cut filter.
The table and other items were starting to get wet by the time that I went back outside to shoot Jupiter, but the dew was not as heavy as the night before. The SCT corrector plate remained completely dry. The humidity was 38% when I came back in the house at 0050.
I do not have a to-do items nor any hindsight regrets from this session. Set up, power up, polar alignment and target acquisition all went rather smoothly.
Nothing conclusive about the UV/IR cut filter. I am hoping to see a difference in the processed images.
