Cassiopeia Observatory

Crescent Moon, NGC2685 Polar-Ring Galaxy

Posted: 13 January 2013

About an hour after sunset on Saturday, 12 January 2013, I took these photos of the very thin crescent (~30 hour old) moon at sunset. The first was taken at 1814 MST, f/5, 1/60sec, ISO 1600, 102mm, and the second at 1832 MST, f/5.3, 1/20sec, ISO 1600, 200mm.

The observatory was opened at 2141 MST, 28°F. The sky was clear. This was planned to be a short session due to the low temperature, with just one goal: image NGC2685, another "polar-ring" galaxy. At 2152 MST, I observed this galaxy at 77X. It was a faint, small, fuzzy "dot". The "ring" was not visible. I then began setting up for imaging using the D7000 DSLR at prime focus of the 8" LX200-ACF. The camera was attached to the telescope using an Off-Axis Guider. A focus test image was done on the star Pollux using a Bahtinov Mask.

I began searching for a guide star and doing framing test exposures of NGC2685. I eventually found a faint star guide star (visible using averted vision) and did a 5 minute, ISO 6400, guided exposure. The image was cropped, and processed using Neat Image to remove noise. This is the result, with the "ring" faintly visible (oriented vertically):

I plan to re-image NGC660 (captured on the two previous sessions) and NGC2685 "polar-ring" galaxies using longer exposures.

Imaging was completed at 2229 MST and the observatory was closed at 2249 MST, 25°F.

Comments are welcome; use the Comments section below, or you can Email Me. Thanks.

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