M71
NGC 6838 · Globular cluster in Sagitta
- Magnitude
- 8.2
- Size
- 7′
- Effective surface brightness
- 20.8 mag/arcsec²
- Best months
- Jun, Jul, Aug
- Declination
- +19°
- Filter
- None (broadband target)
A loose globular in Sagitta that was long mistaken for an open cluster. Rich Milky Way background.
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 | 16% | 9 min57 subs | 13 min80 subs | 30 min180 subs |
| ZWO Seestar S50 Pro10 s subs | 8% | 10 min63 subs | 15 min88 subs | 33 min196 subs |
| ZWO Seestar S3010 s subs | 10% | 10 min62 subs | 14 min85 subs | 31 min185 subs |
| ZWO Seestar S30 Pro10 s subs | 5% | 11 min67 subs | 15 min93 subs | 34 min207 subs |
| DwarfLab DWARF 315 s subs | 7% | 13 min53 subs | 19 min77 subs | 45 min180 subs |
| DwarfLab DWARF mini15 s subs | 10% | 9 min38 subs | 13 min53 subs | 30 min120 subs |
| DwarfLab Draco30 s subs | 9% | 15 min30 subs | 15 min30 subs | 25 min50 subs |
| DwarfLab DWARF II15 s subs | 7% | 36 min146 subs | 47 min188 subs | 1 h 33 min374 subs |
| Vaonis Vespera II10 s subs | 8% | 9 min57 subs | 13 min80 subs | 30 min180 subs |
| Vaonis Vespera Pro10 s subs | 7% | 22 min133 subs | 30 min181 subs | 1 h 05 min392 subs |
| Vaonis Vespera 310 s subs | 8% | 9 min55 subs | 13 min77 subs | 29 min173 subs |
| Vaonis Vespera Pro 210 s subs | 7% | 21 min126 subs | 29 min172 subs | 1 h 02 min375 subs |
| Unistellar eQuinox 24 s subs | 20% | 10 min156 subs | 13 min191 subs | 23 min347 subs |
| Unistellar Odyssey4 s subs | 21% | 52 min774 subs | 1 h904 subs | 1 h 38 min1,472 subs |
| Celestron Origin10 s subs | 14% | 5 min30 subs | 5 min30 subs | 8 min50 subs |
| Celestron Origin Mark II10 s subs | 16% | 5 min30 subs | 5 min30 subs | 12 min70 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 M71 with the ZWO Seestar S50
- How long to image the M71 with the ZWO Seestar S50 Pro
- How long to image the M71 with the ZWO Seestar S30
- How long to image the M71 with the ZWO Seestar S30 Pro
- How long to image the M71 with the DwarfLab DWARF 3
- How long to image the M71 with the DwarfLab DWARF mini
- How long to image the M71 with the DwarfLab Draco
- How long to image the M71 with the DwarfLab DWARF II
- How long to image the M71 with the Vaonis Vespera II
- How long to image the M71 with the Vaonis Vespera Pro
- How long to image the M71 with the Vaonis Vespera 3
- How long to image the M71 with the Vaonis Vespera Pro 2
- How long to image the M71 with the Unistellar eQuinox 2
- How long to image the M71 with the Unistellar Odyssey
- How long to image the M71 with the Celestron Origin
- How long to image the M71 with the Celestron Origin Mark II