How long to image the Crab Nebula with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 2 h 32 min (2,286 subs of 4 s) for a solid image of the Crab Nebula. A quick look takes 38 min; a showpiece 10 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 45 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 | 25 min377 subs | 1 h 40 min1,508 subs | 6 h 42 min6,030 subs |
| Bortle 2Typical dark site | 26 min383 subs | 1 h 42 min1,532 subs | 6 h 48 min6,125 subs |
| Bortle 3Rural | 26 min395 subs | 1 h 45 min1,577 subs | 7 h6,306 subs |
| Bortle 4Rural / suburban transition | 28 min422 subs | 1 h 52 min1,686 subs | 7 h 30 min6,744 subs |
| Bortle 5Suburban | 31 min465 subs | 2 h 04 min1,860 subs | 8 h 16 min7,438 subs |
| Bortle 6Bright suburban | 38 min572 subs | 2 h 32 min2,286 subs | 10 h9,141 subs |
| Bortle 7Suburban / urban transition | 52 min775 subs | 3 h 26 min3,097 subs | 14 h12,385 subs |
| Bortle 8City | 1 h 13 min1,089 subs | 4 h 50 min4,356 subs | 19 h17,423 subs |
| Bortle 9Inner city | 1 h 57 min1,761 subs | 7 h 49 min7,042 subs | 31 h28,167 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 18 min of run time. The Odyssey’s battery is rated at about 5 h, less near freezing, which is cutting it fine; take a power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a December night.)
- 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.
- hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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How it frames
The Crab Nebula is 6′ × 4′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 18% of the frame’s short side.
Filters
The Crab 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 Crab Nebula
The remains of the supernova of 1054, a tangle of filaments around a pulsar. Small but bright enough for a good result in an evening.
M1, NGC 1952 · Supernova remnant in Taurus · magnitude 8.4 · 6′ × 4′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Supernova remnants are emission-line objects, strong in both hydrogen-alpha and OIII, and their filaments are thin, so pixel scale matters as much as aperture. A dual-band filter is essential from any lit sky and still helps under a dark one. These are long-integration targets; plan on several sessions and stack across nights.
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 Crab Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Crab Nebula with the ZWO Seestar S50: 28 min from Bortle 6
- Crab Nebula with the ZWO Seestar S50 Pro: 31 min from Bortle 6
- Crab Nebula with the ZWO Seestar S30: 31 min from Bortle 6
- Crab Nebula with the ZWO Seestar S30 Pro: 33 min from Bortle 6
- Crab Nebula with the DwarfLab DWARF 3: 37 min from Bortle 6
- Crab Nebula with the DwarfLab DWARF mini: 28 min from Bortle 6
- Crab Nebula with the DwarfLab Draco: 22 min from Bortle 6
- Crab Nebula with the DwarfLab DWARF II: 2 h 08 min from Bortle 6
- Crab Nebula with the Vaonis Vespera II: 38 min from Bortle 6
- Crab Nebula with the Vaonis Vespera Pro: 1 h 25 min from Bortle 6
- Crab Nebula with the Vaonis Vespera 3: 37 min from Bortle 6
- Crab Nebula with the Vaonis Vespera Pro 2: 1 h 21 min from Bortle 6
- Crab Nebula with the Unistellar eQuinox 2: 34 min from Bortle 6
- Crab Nebula with the Celestron Origin: 10 min from Bortle 6
- Crab Nebula with the Celestron Origin Mark II: 14 min from Bortle 6
All telescopes for the Crab Nebula · All targets for the Odyssey