Lagoon Nebula
M8, NGC 6523 · Emission nebula in Sagittarius
- Magnitude
- 6.0
- Size
- 90′ × 40′
- Effective surface brightness
- 21.5 mag/arcsec²
- Best months
- Jun, Jul, Aug
- Declination
- -24°
- Filter
- Dual-band recommended
The showpiece emission nebula of the summer Milky Way, bright enough to catch its core in minutes. Pair it with the Trifid in one wide frame.
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 | 22 min135 subs | 24 min147 subs | 33 min198 subs |
| ZWO Seestar S50 Pro10 s subs, dual-band | 17 min100 subs | 19 min113 subs | 28 min169 subs |
| ZWO Seestar S3010 s subs, dual-band | 15 min89 subs | 17 min101 subs | 25 min152 subs |
| ZWO Seestar S30 Pro10 s subs, dual-band | 18 min108 subs | 20 min122 subs | 30 min180 subs |
| DwarfLab Dwarf 315 s subs, dual-band | 24 min97 subs | 27 min109 subs | 40 min162 subs |
| DwarfLab Dwarf Mini15 s subs, dual-band | 13 min51 subs | 15 min59 subs | 23 min94 subs |
| DwarfLab Dwarf II15 s subs | 51 min203 subs | 1 h 08 min274 subs | 2 h 26 min586 subs |
| Vaonis Vespera II10 s subs | 12 min73 subs | 19 min112 subs | 47 min280 subs |
| Vaonis Vespera Pro10 s subs | 34 min204 subs | 47 min285 subs | 1 h 46 min639 subs |
| Unistellar eQuinox 24 s subs | 15 min226 subs | 19 min286 subs | 37 min548 subs |
| Unistellar Odyssey4 s subs | 1 h 18 min1,172 subs | 1 h 33 min1,391 subs | 2 h 36 min2,346 subs |
| Celestron Origin10 s subs | 5 min30 subs | 5 min30 subs | 13 min77 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 Lagoon Nebula with the ZWO Seestar S50
- How long to image the Lagoon Nebula with the ZWO Seestar S50 Pro
- How long to image the Lagoon Nebula with the ZWO Seestar S30
- How long to image the Lagoon Nebula with the ZWO Seestar S30 Pro
- How long to image the Lagoon Nebula with the DwarfLab Dwarf 3
- How long to image the Lagoon Nebula with the DwarfLab Dwarf Mini
- How long to image the Lagoon Nebula with the DwarfLab Dwarf II
- How long to image the Lagoon Nebula with the Vaonis Vespera II
- How long to image the Lagoon Nebula with the Vaonis Vespera Pro
- How long to image the Lagoon Nebula with the Unistellar eQuinox 2
- How long to image the Lagoon Nebula with the Unistellar Odyssey
- How long to image the Lagoon Nebula with the Celestron Origin