 |
| Image | M 4 = NGC 6121 |
| EXIF Time | 2010/05/23 16:39:40 UTC - 17:33:06 UTC |
| Place | Mt. Guizi, Wuchang, Hubei Province, China |
| Optics | Skywatcher 130-mm reflector f/5 |
| Camera | Canon EOS 400D (ISO 1600) |
| Mount | NEQ6 Pro |
| Exposure | 20 s x 29 frames |
| Processing | 29 images stacked in DeepSkyStacker 3.2.2 with dark frames subtracted and flatfield divided; fixed with Fitswork V4.25, IRIS V5.33 and Photoshop CS3 Extended; 0.5x resized and cropped; |
| Comments | images taken by Zhu Mao and processed by me; severe city light pollution; not in focus accurately; obvious coma abberation due to coarce collimation; |