Wallpaper author:
John Ebersole
19 May 2026
M21
The open star cluster, M21, at image center is rather inconspicuous compared to the surrounding nebulae, including M8, M20, Sh2-29, and Sh2-34 at image right, that I recently named the Forgotten Nebula. It suffers the fate of many nice nebulae that are close to famous ones.
Dataset from which the image was processed
M21
8 credit
- Type of target............................................................................................................................Emission Nebula
- Camera............................................................................................................................FLI PL16803
- Target coordinates............................................................................................................................RA 271.0542 Dec -22.48333
- Hemisphere............................................................................................................................Southern
- Telescope location............................................................................................................................Australia
- Transient event............................................................................................................................No
- Observed on............................................................................................................................19 Jun 2021 - 17 Apr 2022
Filter | Avg Exp (s) | Total Exposure | Subframes |
|---|---|---|---|
| SII | 600 | 3h40m | 22 |
| Halpha | 600 | 3h40m | 22 |
| OIII | 600 | 3h40m | 22 |