How long to image the M69 with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 1 h 05 min (982 subs of 4 s) for a solid image of the M69. A quick look takes 16 min; a showpiece 4 h 22 min. Under a Bortle 3 rural sky the solid figure drops to 46 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 29% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 11 min165 subs | 44 min658 subs | 2 h 55 min2,630 subs |
| Bortle 2Typical dark site | 11 min167 subs | 44 min668 subs | 2 h 58 min2,670 subs |
| Bortle 3Rural | 11 min172 subs | 46 min687 subs | 3 h 03 min2,745 subs |
| Bortle 4Rural / suburban transition | 12 min183 subs | 49 min732 subs | 3 h 15 min2,928 subs |
| Bortle 5Suburban | 13 min202 subs | 54 min805 subs | 3 h 34 min3,218 subs |
| Bortle 6Bright suburban | 16 min246 subs | 1 h 05 min982 subs | 4 h 22 min3,928 subs |
| Bortle 7Suburban / urban transition | 22 min331 subs | 1 h 28 min1,321 subs | 5 h 52 min5,282 subs |
| Bortle 8City | 31 min462 subs | 2 h 03 min1,846 subs | 8 h 12 min7,384 subs |
| Bortle 9Inner city | 49 min742 subs | 3 h 18 min2,967 subs | 13 h11,866 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 25 min of run time. The Odyssey’s battery (rated about 5 h) should cover it; a power bank still keeps the phone running the app alive. (Bortle 6, solid image; we allow 30% over the integration time.)
- USB power bank 20000mAh 5V 2.4AUnistellar says plain 5 V 2.4 A and warns against fast or adaptive chargers.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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Everything that fits the Odyssey →
How it frames
The M69 is 9.8′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 29% of the frame’s short side.
About the M69
A small, metal-rich globular near the Sagittarius teapot's base. Low from the north.
NGC 6637 · Globular cluster in Sagittarius · magnitude 7.6 · 9.8′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
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.
About the Unistellar Odyssey
Unistellar’s compact 85 mm with autofocus and tiny pixels. Sharp, but the fine sampling costs time on faint extended targets. The Odyssey Pro is the same telescope with an eyepiece added, so these figures apply to both.
Fixed 4 s subs in Enhanced Vision; they cannot be changed. No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey.
The Odyssey uses fixed 4 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.
Stack across nights. Every smart scope app can continue a stack or you can combine the saved frames on a computer; the figures here are totals, not single-session limits.
Have an image of the M69 from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M69 with the ZWO Seestar S50: 17 min from Bortle 6
- M69 with the ZWO Seestar S50 Pro: 18 min from Bortle 6
- M69 with the ZWO Seestar S30: 18 min from Bortle 6
- M69 with the ZWO Seestar S30 Pro: 19 min from Bortle 6
- M69 with the DwarfLab DWARF 3: 25 min from Bortle 6
- M69 with the DwarfLab DWARF mini: 17 min from Bortle 6
- M69 with the DwarfLab Draco: 15 min from Bortle 6
- M69 with the DwarfLab DWARF II: 56 min from Bortle 6
- M69 with the Vaonis Vespera II: 17 min from Bortle 6
- M69 with the Vaonis Vespera Pro: 37 min from Bortle 6
- M69 with the Vaonis Vespera 3: 16 min from Bortle 6
- M69 with the Vaonis Vespera Pro 2: 36 min from Bortle 6
- M69 with the Unistellar eQuinox 2: 15 min from Bortle 6
- M69 with the Celestron Origin: 5 min from Bortle 6
- M69 with the Celestron Origin Mark II: 6 min from Bortle 6