Cassiopeia Observatory

Frustrating Night of Imaging

Posted: 10 June 2012

Opened the observatory Saturday, 9 June, at 1915 MST, 92°F. The sky was clear but there was a strong wind at times. I had two activities planned for the night: image an ISS pass and redo four small faint galaxies that I had done on the previous session whose exposures had trailed. I waited for the wind to calm down some before powering on the telescope. At sunset, the wind calmed down somewhat. But this hawk was finding it easy to soar:

I started up the telescope at 1940 MST and began preparing for the upcoming ISS pass. Updated the ISS TLE. Mounted the D7000 DSLR at prime focus of the 8" LX200-ACF. Did a focus test with the Bahtinov Mask on Spica and locked the focus. Checked the finderscope alignment and made a slight adjustment. At 1948 MST, I was ready for the ISS pass to begin at 2010 MST. There was still an occasional strong breeze.

The start of the pass was off by several seconds and initial pointing was way off. I eventually got the ISS centered in the finderscope, and once I did, tracking was pretty good. I lost the ISS as it passed near the NCP but regained it shortly afterwards as it headed back down to the horizon. I did a 7m56s HD recording. Unfortunately, the finderscope alignment was off; it must have slipped at some point near the start of the pass. Only a few video frames had the ISS and those were too blurry to be useful. Fortunately, this ISS pass was not an ideal one as it was low along the horizon, making the station a long way from me.

At 2025 MST, viewed Saturn at 77X, 133X, 206X, and 364X. Four moons were visible.

At 2031 MST, I began preps for the DSO imaging. I mounted the D7000 in a different orientation of the Off-Axis Guider (OAG) from what I had used on the previous night in the hopes of acquiring better guide stars. Did another focus test. I planned to re-image four galaxies and do a fifth one (NGC6217). The guide stars I was able to find this night were mostly faint or in one case, non-existent. Some problems also occurred. The OAG sometimes slipped, requiring a refocus. The camera ran into something on the mount, requiring a realignment of the GOTO system. I did manage to capture these three (of the five planned) images, slightly cropped (to the same scale), guided, 5 minutes, ISO 6400:

I ended imaging at 2249 MST. Redid the AutoStar alignment. At 2310 MST, I needed some relaxation after all the difficulties and so viewed M20 (Trifid Nebula), M8 (Lagoon Nebula), and M17 (Swan Nebula), all at 77X.

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