How long to image the Ring Nebula with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 28 min (422 subs of 4 s) for a solid image of the Ring Nebula. A quick look takes 7 min; a showpiece 1 h 52 min. Under a Bortle 3 rural sky the solid figure drops to 21 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 4% 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 | 5 min75 subs | 20 min299 subs | 1 h 19 min1,193 subs |
| Bortle 2Typical dark site | 5 min76 subs | 20 min302 subs | 1 h 20 min1,208 subs |
| Bortle 3Rural | 5 min78 subs | 21 min309 subs | 1 h 22 min1,236 subs |
| Bortle 4Rural / suburban transition | 5 min82 subs | 22 min327 subs | 1 h 27 min1,306 subs |
| Bortle 5Suburban | 6 min89 subs | 24 min354 subs | 1 h 34 min1,416 subs |
| Bortle 6Bright suburban | 7 min106 subs | 28 min422 subs | 1 h 52 min1,686 subs |
| Bortle 7Suburban / urban transition | 9 min138 subs | 37 min550 subs | 2 h 27 min2,200 subs |
| Bortle 8City | 12 min188 subs | 50 min750 subs | 3 h 20 min2,998 subs |
| Bortle 9Inner city | 20 min294 subs | 1 h 18 min1,176 subs | 5 h 13 min4,701 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 37 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 Ring Nebula is 1.4′ × 1′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 4% of the frame’s short side.
Filters
The Ring Nebula is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the Odyssey has no dual-band option: No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey. The figures above are for the No filter position, and a darker sky is the lever that remains.
About the Ring Nebula
A tiny, bright smoke ring. It is small in a smart scope but so bright per pixel that a few minutes show the ring; the faint outer halo is another matter.
M57, NGC 6720 · Planetary nebula in Lyra · magnitude 8.8 · 1.4′ × 1′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
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 Ring Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Ring Nebula with the ZWO Seestar S50: 7 min from Bortle 6
- Ring Nebula with the ZWO Seestar S50 Pro: 8 min from Bortle 6
- Ring Nebula with the ZWO Seestar S30: 7 min from Bortle 6
- Ring Nebula with the ZWO Seestar S30 Pro: 8 min from Bortle 6
- Ring Nebula with the DwarfLab DWARF 3: 10 min from Bortle 6
- Ring Nebula with the DwarfLab DWARF mini: 8 min from Bortle 6
- Ring Nebula with the DwarfLab Draco: 15 min from Bortle 6
- Ring Nebula with the DwarfLab DWARF II: 25 min from Bortle 6
- Ring Nebula with the Vaonis Vespera II: 8 min from Bortle 6
- Ring Nebula with the Vaonis Vespera Pro: 17 min from Bortle 6
- Ring Nebula with the Vaonis Vespera 3: 7 min from Bortle 6
- Ring Nebula with the Vaonis Vespera Pro 2: 16 min from Bortle 6
- Ring Nebula with the Unistellar eQuinox 2: 6 min from Bortle 6
- Ring Nebula with the Celestron Origin: 5 min from Bortle 6
- Ring Nebula with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Ring Nebula · All targets for the Odyssey