M12
NGC 6218 · Globular cluster in Ophiuchus
- Magnitude
- 6.7
- Size
- 16′
- Effective surface brightness
- 21.1 mag/arcsec²
- Best months
- May, Jun, Jul
- Declination
- -2°
- Filter
- None (broadband target)
A looser globular than M10 with a less concentrated core. Fine in a single hour.
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 | 37% | 7 min41 subs | 10 min59 subs | 23 min140 subs |
| ZWO Seestar S50 Pro10 s subs | 19% | 7 min45 subs | 11 min65 subs | 25 min152 subs |
| ZWO Seestar S3010 s subs | 22% | 7 min44 subs | 10 min63 subs | 24 min143 subs |
| ZWO Seestar S30 Pro10 s subs | 12% | 8 min48 subs | 11 min69 subs | 27 min160 subs |
| DwarfLab DWARF 315 s subs | 16% | 9 min37 subs | 14 min56 subs | 35 min139 subs |
| DwarfLab DWARF mini15 s subs | 22% | 8 min30 subs | 10 min39 subs | 23 min93 subs |
| DwarfLab Draco30 s subs | 21% | 15 min30 subs | 15 min30 subs | 19 min39 subs |
| DwarfLab DWARF II15 s subs | 15% | 27 min107 subs | 35 min141 subs | 1 h 12 min290 subs |
| Vaonis Vespera II10 s subs | 19% | 7 min41 subs | 10 min59 subs | 23 min140 subs |
| Vaonis Vespera Pro10 s subs | 16% | 16 min95 subs | 22 min134 subs | 50 min303 subs |
| Vaonis Vespera 310 s subs | 18% | 6 min39 subs | 9 min56 subs | 22 min134 subs |
| Vaonis Vespera Pro 210 s subs | 16% | 15 min90 subs | 21 min127 subs | 48 min290 subs |
| Unistellar eQuinox 24 s subs | 47% | 8 min117 subs | 10 min145 subs | 18 min271 subs |
| Unistellar Odyssey4 s subs | 48% | 39 min591 subs | 46 min696 subs | 1 h 17 min1,152 subs |
| Celestron Origin10 s subs | 31% | 5 min30 subs | 5 min30 subs | 6 min39 subs |
| Celestron Origin Mark II10 s subs | 36% | 5 min30 subs | 5 min30 subs | 9 min54 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 M12 with the ZWO Seestar S50
- How long to image the M12 with the ZWO Seestar S50 Pro
- How long to image the M12 with the ZWO Seestar S30
- How long to image the M12 with the ZWO Seestar S30 Pro
- How long to image the M12 with the DwarfLab DWARF 3
- How long to image the M12 with the DwarfLab DWARF mini
- How long to image the M12 with the DwarfLab Draco
- How long to image the M12 with the DwarfLab DWARF II
- How long to image the M12 with the Vaonis Vespera II
- How long to image the M12 with the Vaonis Vespera Pro
- How long to image the M12 with the Vaonis Vespera 3
- How long to image the M12 with the Vaonis Vespera Pro 2
- How long to image the M12 with the Unistellar eQuinox 2
- How long to image the M12 with the Unistellar Odyssey
- How long to image the M12 with the Celestron Origin
- How long to image the M12 with the Celestron Origin Mark II