Rosette Nebula
NGC 2237, NGC 2244, Caldwell 49 · Emission nebula in Monoceros
- Magnitude
- 9.0
- 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 | In frame | Bortle 3 (rural) | Bortle 5 (suburban) | Bortle 7 (urban edge) |
|---|---|---|---|---|
| ZWO Seestar S5010 s subs, dual-band | 1.9× frame | 59 min357 subs | 1 h 10 min419 subs | 1 h 55 min690 subs |
| ZWO Seestar S50 Pro10 s subs, dual-band | Only just | 1 h 08 min407 subs | 1 h 19 min474 subs | 2 h 08 min766 subs |
| ZWO Seestar S3010 s subs, dual-band | 1.1× frame | 1 h 14 min442 subs | 1 h 24 min504 subs | 2 h 09 min775 subs |
| ZWO Seestar S30 Pro10 s subs, dual-band | 59% | 1 h 14 min443 subs | 1 h 25 min513 subs | 2 h 17 min821 subs |
| DwarfLab DWARF 315 s subs, dual-band | 81% | 1 h 06 min264 subs | 1 h 22 min328 subs | 2 h 32 min607 subs |
| DwarfLab DWARF mini15 s subs, dual-band | 1.1× frame | 58 min233 subs | 1 h 08 min274 subs | 1 h 54 min455 subs |
| DwarfLab Draco30 s subs, dual-band | 1.1× frame | 46 min92 subs | 55 min110 subs | 1 h 32 min185 subs |
| DwarfLab DWARF II15 s subs | 74% | 3 h 50 min922 subs | 5 h 24 min1,297 subs | 12 h2,934 subs |
| Vaonis Vespera II10 s subs | Only just | 51 min306 subs | 1 h 25 min509 subs | 3 h 52 min1,393 subs |
| Vaonis Vespera Pro10 s subs | 82% | 2 h 06 min757 subs | 3 h 17 min1,182 subs | 8 h 27 min3,041 subs |
| Vaonis Vespera 310 s subs | Only just | 48 min290 subs | 1 h 21 min484 subs | 3 h 42 min1,334 subs |
| Vaonis Vespera Pro 210 s subs | 81% | 1 h 59 min713 subs | 3 h 07 min1,122 subs | 8 h 05 min2,908 subs |
| Unistellar eQuinox 24 s subs | 2.3× frame | 1 h 11 min1,064 subs | 1 h 32 min1,379 subs | 3 h 04 min2,757 subs |
| Unistellar Odyssey4 s subs | 2.4× frame | 6 h 21 min5,721 subs | 7 h 38 min6,868 subs | 13 h11,882 subs |
| Celestron Origin10 s subs | 1.6× frame | 12 min72 subs | 21 min129 subs | 1 h 03 min380 subs |
| Celestron Origin Mark II10 s subs | 1.8× frame | 15 min88 subs | 28 min171 subs | 1 h 29 min532 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, or Expert Mode on a Vespera) 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 Draco
- 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 Vaonis Vespera 3
- How long to image the Rosette Nebula with the Vaonis Vespera Pro 2
- 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
- How long to image the Rosette Nebula with the Celestron Origin Mark II