How long to image the M103 with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 20 min (306 subs of 4 s) for a solid image of the M103. A quick look takes 5 min; a showpiece 1 h 21 min. Under a Bortle 3 rural sky the solid figure drops to 15 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 18% 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 | 4 min55 subs | 15 min220 subs | 59 min880 subs |
| Bortle 2Typical dark site | 4 min56 subs | 15 min223 subs | 59 min891 subs |
| Bortle 3Rural | 4 min57 subs | 15 min228 subs | 1 h 01 min910 subs |
| Bortle 4Rural / suburban transition | 4 min60 subs | 16 min240 subs | 1 h 04 min958 subs |
| Bortle 5Suburban | 4 min65 subs | 17 min259 subs | 1 h 09 min1,035 subs |
| Bortle 6Bright suburban | 5 min77 subs | 20 min306 subs | 1 h 21 min1,221 subs |
| Bortle 7Suburban / urban transition | 7 min99 subs | 26 min395 subs | 1 h 45 min1,577 subs |
| Bortle 8City | 9 min134 subs | 35 min533 subs | 2 h 22 min2,129 subs |
| Bortle 9Inner city | 14 min207 subs | 55 min827 subs | 3 h 40 min3,308 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 26 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 M103 is 6′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 18% of the frame’s short side.
About the M103
A small, fan-shaped open cluster in Cassiopeia, the last object in Messier's own list.
NGC 581 · Open cluster in Cassiopeia · magnitude 7.4 · 6′ · best in Sep, Oct, Nov. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Open clusters are the easiest targets in the sky. The stars are bright, so the aim is colour and tight stars rather than depth: short subs, no filter, and stop before the bright members saturate. The nominal time here gets you clean star colour; more integration only adds background stars.
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 M103 from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M103 with the ZWO Seestar S50: 6 min from Bortle 6
- M103 with the ZWO Seestar S50 Pro: 6 min from Bortle 6
- M103 with the ZWO Seestar S30: 6 min from Bortle 6
- M103 with the ZWO Seestar S30 Pro: 7 min from Bortle 6
- M103 with the DwarfLab DWARF 3: 9 min from Bortle 6
- M103 with the DwarfLab DWARF mini: 8 min from Bortle 6
- M103 with the DwarfLab Draco: 15 min from Bortle 6
- M103 with the DwarfLab DWARF II: 19 min from Bortle 6
- M103 with the Vaonis Vespera II: 6 min from Bortle 6
- M103 with the Vaonis Vespera Pro: 13 min from Bortle 6
- M103 with the Vaonis Vespera 3: 6 min from Bortle 6
- M103 with the Vaonis Vespera Pro 2: 12 min from Bortle 6
- M103 with the Unistellar eQuinox 2: 5 min from Bortle 6
- M103 with the Celestron Origin: 5 min from Bortle 6
- M103 with the Celestron Origin Mark II: 5 min from Bortle 6