How long to image the M12 with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 57 min (853 subs of 4 s) for a solid image of the M12. A quick look takes 14 min; a showpiece 3 h 47 min. Under a Bortle 3 rural sky the solid figure drops to 39 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 48% 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 | 9 min142 subs | 38 min566 subs | 2 h 31 min2,261 subs |
| Bortle 2Typical dark site | 10 min144 subs | 38 min574 subs | 2 h 33 min2,296 subs |
| Bortle 3Rural | 10 min148 subs | 39 min591 subs | 2 h 37 min2,363 subs |
| Bortle 4Rural / suburban transition | 11 min158 subs | 42 min632 subs | 2 h 48 min2,525 subs |
| Bortle 5Suburban | 12 min174 subs | 46 min696 subs | 3 h 05 min2,781 subs |
| Bortle 6Bright suburban | 14 min214 subs | 57 min853 subs | 3 h 47 min3,409 subs |
| Bortle 7Suburban / urban transition | 19 min288 subs | 1 h 17 min1,152 subs | 5 h 07 min4,607 subs |
| Bortle 8City | 27 min405 subs | 1 h 48 min1,617 subs | 7 h 11 min6,466 subs |
| Bortle 9Inner city | 43 min652 subs | 2 h 54 min2,608 subs | 12 h10,431 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 14 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 M12 is 16′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 48% of the frame’s short side.
About the M12
A looser globular than M10 with a less concentrated core. Fine in a single hour.
NGC 6218 · Globular cluster in Ophiuchus · magnitude 6.7 · 16′ · best in May, Jun, Jul. 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 M12 from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M12 with the ZWO Seestar S50: 14 min from Bortle 6
- M12 with the ZWO Seestar S50 Pro: 16 min from Bortle 6
- M12 with the ZWO Seestar S30: 15 min from Bortle 6
- M12 with the ZWO Seestar S30 Pro: 17 min from Bortle 6
- M12 with the DwarfLab DWARF 3: 21 min from Bortle 6
- M12 with the DwarfLab DWARF mini: 14 min from Bortle 6
- M12 with the DwarfLab Draco: 15 min from Bortle 6
- M12 with the DwarfLab DWARF II: 48 min from Bortle 6
- M12 with the Vaonis Vespera II: 14 min from Bortle 6
- M12 with the Vaonis Vespera Pro: 32 min from Bortle 6
- M12 with the Vaonis Vespera 3: 14 min from Bortle 6
- M12 with the Vaonis Vespera Pro 2: 30 min from Bortle 6
- M12 with the Unistellar eQuinox 2: 13 min from Bortle 6
- M12 with the Celestron Origin: 5 min from Bortle 6
- M12 with the Celestron Origin Mark II: 5 min from Bortle 6