West Veil Nebula (NGC6960) and Equipment Tuning

My objective for this session was to image the West Veil Nebula while getting a much needed DSO imaging refresher in preparation for a trip to the Farm. The bottom-line result is that I discovered that I really would not have been ready for the farm last night.

The difficulty was with the remote desktop connection. I established the connection during the afternoon so that I could wring out any issues with connecting software to devices. The remote connection itself worked perfectly. I uncovered a problem with the filter wheel that took a little while to find, but everything looked set to go for an imaging session. I left the connection in place when I went in for dinner, and it was still working just fine when I cam back to the scope at 2010, and it continued to work perfectly as I did a star alignment, calibrated PHD and executed a guiding assistant run, acquired the target and started the exposure sequence. The connection dropped exactly when I started the capture sequence, and I couldn’t get it back even with Ethernet. I had set the sequence for 25 x 60s exposures in RG and B. Not sure how long it would take, because I forgot to check my dither setting before starting execution. I usually set it for every 3rd exposure to minimize the time impact. I decided to let the sequence run until I went to bed so that if it was executing correctly that I would have something in the morning. I’ll check the mini computer to see if there is any data this afternoon.

My theory was that the mini computer was saving the images to OneDrive across the wifi connection, and that was somehow disrupting the remote desktop connection. This morning I realized that I should see images on OneDrive if that were the case, and so far I haven’t found them.

The good part about last night was the guiding performance. Calibration completed in about 30s with a perfect graph. The guiding assistant showed that my polar alignment error was about 4’, which is acceptable, but once guiding stopped for the GA run I could see the dec plot trending down at a fairly gently slope that I assessed as easily guided out. My Dec backlash was 2100, which about the same as before I adjusted. I got a good backlash graph where the downhill slope of the actual movement was just to the right of and parallel to the ideal movement, which means that the Dec axis is responsive to guiding impulses. I attribute this to east-bias balance on Ra and I had the bright idea of balancing the Dec axis with the scope slightly tail heavy. My initial guiding was about .67”, the best I have seen.

End of astronomical twilight was 2127, and I was imaging by 2129.

In hindsight, I wish that I had:

…used the Drift Alignment tool to fine tune the polar alignment. The guiding was great as it was, but it is really cool to see the Dec ticking along without any guiding pulses. I think that I can do the Drift alignment tweak in just a few minutes, and the time burden will decrease with practice. With the Gemini Level 6 improvements, which include better PEC training, perhaps one day Ra guiding pulses can be minimized.

…used my written guide. Due to weather and lunar cycle, it has been over a month since I last did DSO work. I missed at least four little things as a result of not using my guide. It turns out that I am not as smart as I think I am.

…stuck with my original plan. I kinda rushed to completion of guiding preliminaries as 2127 approached, and my session was essentially over when I started the imaging sequence at 2129. I could have improved understanding of guiding by a useful amount if I had worked with it for an hour more.

To-do list items:

Figure out remote connection once and for all.

Camera cooling was working, but there was no cooling graph.  

The week that I have spent on finding, purchasing, and getting familiar with the camper was the time period that I would have ordinarily spent doing planetary imaging and getting ready for DSO imaging when the moon went away. I knew going in might be behind the curve when the first opportunity for DSO imaging came back. But that’s ok. It was worth it to have a ready camper as cooler weather is not that far away. Besides, it looks like the next imaging opportunity is some time off, so hopefully I can get back on the curve over the next few days.

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