Rosette Nebula
NGC 2237, NGC 2244, Caldwell 49 · Emission nebula in Monoceros
- Magnitude
- 6.0
- Size
- 80′ × 60′
- Effective surface brightness
- 22.4 mag/arcsec²
- Best months
- Dec, Jan, Feb
- Declination
- +5°
- Filter
- Dual-band recommended
A ring of hydrogen more than a degree across around the cluster NGC 2244. One of the best dual-band targets of winter and forgiving of light pollution.
Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
How long with each smart telescope
| Telescope | Bortle 3 (rural) | Bortle 5 (suburban) | Bortle 7 (urban edge) |
|---|---|---|---|
| ZWO Seestar S5010 s subs, dual-band | 1 h 40 min599 subs | 1 h 50 min661 subs | 2 h 35 min932 subs |
| ZWO Seestar S50 Pro10 s subs, dual-band | 1 h 08 min407 subs | 1 h 19 min474 subs | 2 h 08 min766 subs |
| ZWO Seestar S3010 s subs, dual-band | 59 min357 subs | 1 h 10 min419 subs | 1 h 55 min690 subs |
| ZWO Seestar S30 Pro10 s subs, dual-band | 1 h 14 min443 subs | 1 h 25 min513 subs | 2 h 17 min821 subs |
| DwarfLab Dwarf 315 s subs, dual-band | 1 h 39 min395 subs | 1 h 55 min459 subs | 3 h 04 min738 subs |
| DwarfLab Dwarf Mini15 s subs, dual-band | 49 min195 subs | 59 min237 subs | 1 h 44 min417 subs |
| DwarfLab Dwarf II15 s subs | 3 h 50 min922 subs | 5 h 24 min1,297 subs | 12 h2,934 subs |
| Vaonis Vespera II10 s subs | 51 min306 subs | 1 h 25 min509 subs | 3 h 52 min1,393 subs |
| Vaonis Vespera Pro10 s subs | 2 h 31 min908 subs | 3 h 42 min1,333 subs | 8 h 52 min3,192 subs |
| Unistellar eQuinox 24 s subs | 1 h 11 min1,064 subs | 1 h 32 min1,379 subs | 3 h 04 min2,757 subs |
| Unistellar Odyssey4 s subs | 6 h 21 min5,721 subs | 7 h 38 min6,868 subs | 13 h11,882 subs |
| Celestron Origin10 s subs | 12 min72 subs | 21 min129 subs | 1 h 03 min380 subs |
Imaging the emission nebula
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
Per-telescope pages
- How long to image the Rosette Nebula with the ZWO Seestar S50
- How long to image the Rosette Nebula with the ZWO Seestar S50 Pro
- How long to image the Rosette Nebula with the ZWO Seestar S30
- How long to image the Rosette Nebula with the ZWO Seestar S30 Pro
- How long to image the Rosette Nebula with the DwarfLab Dwarf 3
- How long to image the Rosette Nebula with the DwarfLab Dwarf Mini
- How long to image the Rosette Nebula with the DwarfLab Dwarf II
- How long to image the Rosette Nebula with the Vaonis Vespera II
- How long to image the Rosette Nebula with the Vaonis Vespera Pro
- How long to image the Rosette Nebula with the Unistellar eQuinox 2
- How long to image the Rosette Nebula with the Unistellar Odyssey
- How long to image the Rosette Nebula with the Celestron Origin