How long to image the Little Dumbbell with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 3 h 01 min (2,722 subs of 4 s) for a solid image of the Little Dumbbell. A quick look takes 45 min; a showpiece 12 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 05 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 8% 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 | 30 min447 subs | 1 h 59 min1,787 subs | 7 h 56 min7,145 subs |
| Bortle 2Typical dark site | 30 min454 subs | 2 h 01 min1,815 subs | 8 h 04 min7,260 subs |
| Bortle 3Rural | 31 min468 subs | 2 h 05 min1,870 subs | 8 h 18 min7,477 subs |
| Bortle 4Rural / suburban transition | 33 min501 subs | 2 h 13 min2,001 subs | 8 h 54 min8,003 subs |
| Bortle 5Suburban | 37 min553 subs | 2 h 27 min2,210 subs | 9 h 49 min8,838 subs |
| Bortle 6Bright suburban | 45 min681 subs | 3 h 01 min2,722 subs | 12 h10,885 subs |
| Bortle 7Suburban / urban transition | 1 h 02 min925 subs | 4 h 06 min3,697 subs | 16 h14,786 subs |
| Bortle 8City | 1 h 27 min1,303 subs | 5 h 47 min5,211 subs | 23 h20,843 subs |
| Bortle 9Inner city | 2 h 21 min2,110 subs | 9 h 23 min8,440 subs | 38 h33,760 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 56 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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How it frames
The Little Dumbbell is 2.7′ × 1.8′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 8% of the frame’s short side.
Filters
The Little Dumbbell 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 Little Dumbbell
A small, bright-per-pixel planetary in Perseus. Dual-band makes the two lobes and the faint wings much easier.
M76, NGC 650 · Planetary nebula in Perseus · magnitude 10.1 · 2.7′ × 1.8′ · best in Sep, Oct, Nov. 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 Little Dumbbell from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Little Dumbbell with the ZWO Seestar S50: 33 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S50 Pro: 36 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S30: 37 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S30 Pro: 39 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF 3: 43 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF mini: 32 min from Bortle 6
- Little Dumbbell with the DwarfLab Draco: 26 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF II: 2 h 32 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera II: 45 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera Pro: 1 h 41 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera 3: 43 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera Pro 2: 1 h 36 min from Bortle 6
- Little Dumbbell with the Unistellar eQuinox 2: 40 min from Bortle 6
- Little Dumbbell with the Celestron Origin: 12 min from Bortle 6
- Little Dumbbell with the Celestron Origin Mark II: 17 min from Bortle 6
All telescopes for the Little Dumbbell · All targets for the Odyssey