How long to image the Dumbbell Nebula with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 1 h 47 min (1,601 subs of 4 s) for a solid image of the Dumbbell Nebula. A quick look takes 27 min; a showpiece 7 h 07 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 14 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 24% 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 | 18 min266 subs | 1 h 11 min1,062 subs | 4 h 43 min4,246 subs |
| Bortle 2Typical dark site | 18 min270 subs | 1 h 12 min1,078 subs | 4 h 47 min4,312 subs |
| Bortle 3Rural | 18 min278 subs | 1 h 14 min1,110 subs | 4 h 56 min4,437 subs |
| Bortle 4Rural / suburban transition | 20 min297 subs | 1 h 19 min1,186 subs | 5 h 16 min4,741 subs |
| Bortle 5Suburban | 22 min327 subs | 1 h 27 min1,306 subs | 5 h 48 min5,222 subs |
| Bortle 6Bright suburban | 27 min401 subs | 1 h 47 min1,601 subs | 7 h 07 min6,402 subs |
| Bortle 7Suburban / urban transition | 36 min541 subs | 2 h 24 min2,163 subs | 9 h 37 min8,651 subs |
| Bortle 8City | 51 min759 subs | 3 h 22 min3,036 subs | 13 h12,143 subs |
| Bortle 9Inner city | 1 h 22 min1,225 subs | 5 h 26 min4,898 subs | 22 h19,590 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 19 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 Dumbbell Nebula is 8′ × 5.7′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 24% of the frame’s short side.
Filters
The Dumbbell 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 Dumbbell Nebula
The biggest, brightest planetary nebula for northern observers. Bright enough to look good in twenty minutes, and dual-band brings out the outer shell.
M27, NGC 6853 · Planetary nebula in Vulpecula · magnitude 7.4 · 8′ × 5.7′ · 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 Dumbbell Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Dumbbell Nebula with the ZWO Seestar S50: 20 min from Bortle 6
- Dumbbell Nebula with the ZWO Seestar S50 Pro: 22 min from Bortle 6
- Dumbbell Nebula with the ZWO Seestar S30: 23 min from Bortle 6
- Dumbbell Nebula with the ZWO Seestar S30 Pro: 24 min from Bortle 6
- Dumbbell Nebula with the DwarfLab DWARF 3: 27 min from Bortle 6
- Dumbbell Nebula with the DwarfLab DWARF mini: 20 min from Bortle 6
- Dumbbell Nebula with the DwarfLab Draco: 16 min from Bortle 6
- Dumbbell Nebula with the DwarfLab DWARF II: 1 h 30 min from Bortle 6
- Dumbbell Nebula with the Vaonis Vespera II: 27 min from Bortle 6
- Dumbbell Nebula with the Vaonis Vespera Pro: 1 h from Bortle 6
- Dumbbell Nebula with the Vaonis Vespera 3: 26 min from Bortle 6
- Dumbbell Nebula with the Vaonis Vespera Pro 2: 57 min from Bortle 6
- Dumbbell Nebula with the Unistellar eQuinox 2: 24 min from Bortle 6
- Dumbbell Nebula with the Celestron Origin: 7 min from Bortle 6
- Dumbbell Nebula with the Celestron Origin Mark II: 10 min from Bortle 6
All telescopes for the Dumbbell Nebula · All targets for the Odyssey