Cassiopeia Observatory

Galaxy Imaging: NGC7479 and NGC7814

Posted: 13 October 2012

Although the sky was clear Wednesday night, 10 October 2012, I had to skip it due to a very early morning commitment on Thursday. And then the sky clouded up on Thursday; another night lost. But the sky cleared on Friday, 12 October 2012, and the observatory was opened at 1812 MST, 71°F. There were some clouds low along the western horizon but I didn't think they would become a problem. At 1818 MST, viewed Mars low in the southwest, 77X; no details visible. At 1828 MST, I slewed to one of the night's planned DSO imaging targets: NGC7814 (galaxy) and began waiting for the sky to get darker. While waiting, I prepared the D7000 DSLR for 8" LX200-ACF prime focus imaging with the Off-Axis Guider (OAG). At 1849 MST, NGC7814 was just barely visible at 77X. I SYNCed the AutoStar II on its position. At 1851 MST, slewed to the other DSO target: NGC7479 (spiral galaxy); it was also just faintly visible at 77X. It would be the first DSO imaged this night.

I then watched a low elevation pass of the International Space Station, 1857-1900 MST. I then mounted the DSLR on the telescope. Did a focus test on the star Alpha Pegasus using the Bahtinov Mask. At 1913 MST, did a framing test exposure of NGC7479. I had located a reasonably good guide star. I then captured this 5 minute, ISO 6400, guided image (cropped) of NGC7479:

I next slewed to NGC7814, searched for a guide star and found a faint one. Did a framing test exposure and then took this (cropped to same scale as NGC7479) 5 minute, ISO 6400, guided exposure:

Guiding during the above exposure was difficult as I had to use averted vision to see the guide star. As a test, I then did 10 1-minute, ISO 6400, unguided exposures for stacking. During post-processing the 10 images were stacked using Lynkeos, for an effective exposure length of 10 minutes, with this result:

I finished DSO imaging at 1959 MST; removed the camera from the telescope. At 2024 MST, noticed that the clouds in the west were now higher in the sky. At 2031 MST, viewed Comet 168P/Hergenrother, 77X. The comet was still a nice object with a short tail. Switched to 133X and monitored the comet motion for the next 20 minutes. After 10 minutes, its movement away from a bright star was evident.

Due to various activities during the daytime, I was getting tired. Decided to close for the night. The observatory was closed at 2107 MST, 54°F.

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