M22
NGC 6656 · Globular cluster in Sagittarius
- Magnitude
- 5.1
- Size
- 32′
- Effective surface brightness
- 21.0 mag/arcsec²
- Best months
- Jun, Jul, Aug
- Declination
- -24°
- Filter
- None (broadband target)
One of the brightest globulars in the sky, outshining M13, but low from northern Europe. Superb from the south.
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 | 74% | 6 min36 subs | 8 min51 subs | 20 min119 subs |
| ZWO Seestar S50 Pro10 s subs | 39% | 6 min39 subs | 9 min56 subs | 21 min129 subs |
| ZWO Seestar S3010 s subs | 45% | 6 min39 subs | 9 min54 subs | 20 min122 subs |
| ZWO Seestar S30 Pro10 s subs | 24% | 7 min42 subs | 10 min59 subs | 23 min136 subs |
| DwarfLab DWARF 315 s subs | 32% | 8 min33 subs | 12 min49 subs | 29 min118 subs |
| DwarfLab DWARF mini15 s subs | 45% | 8 min30 subs | 8 min34 subs | 20 min79 subs |
| DwarfLab Draco30 s subs | 43% | 15 min30 subs | 15 min30 subs | 16 min33 subs |
| DwarfLab DWARF II15 s subs | 30% | 23 min93 subs | 30 min121 subs | 1 h 01 min246 subs |
| Vaonis Vespera II10 s subs | 37% | 6 min36 subs | 8 min51 subs | 20 min119 subs |
| Vaonis Vespera Pro10 s subs | 33% | 14 min83 subs | 19 min115 subs | 43 min258 subs |
| Vaonis Vespera 310 s subs | 36% | 6 min34 subs | 8 min49 subs | 19 min114 subs |
| Vaonis Vespera Pro 210 s subs | 32% | 13 min79 subs | 18 min110 subs | 41 min246 subs |
| Unistellar eQuinox 24 s subs | Only just | 7 min100 subs | 8 min124 subs | 15 min229 subs |
| Unistellar Odyssey4 s subs | Only just | 34 min504 subs | 39 min592 subs | 1 h 05 min975 subs |
| Celestron Origin10 s subs | 62% | 5 min30 subs | 5 min30 subs | 5 min33 subs |
| Celestron Origin Mark II10 s subs | 72% | 5 min30 subs | 5 min30 subs | 8 min46 subs |
Imaging the globular cluster
Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.
Per-telescope pages
- How long to image the M22 with the ZWO Seestar S50
- How long to image the M22 with the ZWO Seestar S50 Pro
- How long to image the M22 with the ZWO Seestar S30
- How long to image the M22 with the ZWO Seestar S30 Pro
- How long to image the M22 with the DwarfLab DWARF 3
- How long to image the M22 with the DwarfLab DWARF mini
- How long to image the M22 with the DwarfLab Draco
- How long to image the M22 with the DwarfLab DWARF II
- How long to image the M22 with the Vaonis Vespera II
- How long to image the M22 with the Vaonis Vespera Pro
- How long to image the M22 with the Vaonis Vespera 3
- How long to image the M22 with the Vaonis Vespera Pro 2
- How long to image the M22 with the Unistellar eQuinox 2
- How long to image the M22 with the Unistellar Odyssey
- How long to image the M22 with the Celestron Origin
- How long to image the M22 with the Celestron Origin Mark II