How long to image the California Nebula with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 14 h (12,341 subs of 4 s) for a solid image of the California Nebula. A quick look takes 3 h 26 min; a showpiece 55 h. Under a Bortle 3 rural sky the solid figure drops to 9 h 06 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is 4.8× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 2 h 10 min1,946 subs | 8 h 39 min7,784 subs | 35 h31,135 subs |
| Bortle 2Typical dark site | 2 h 12 min1,981 subs | 8 h 48 min7,924 subs | 35 h31,695 subs |
| Bortle 3Rural | 2 h 16 min2,048 subs | 9 h 06 min8,189 subs | 36 h32,754 subs |
| Bortle 4Rural / suburban transition | 2 h 27 min2,208 subs | 9 h 49 min8,830 subs | 39 h35,319 subs |
| Bortle 5Suburban | 2 h 44 min2,462 subs | 11 h9,847 subs | 44 h39,386 subs |
| Bortle 6Bright suburban | 3 h 26 min3,086 subs | 14 h12,341 subs | 55 h49,362 subs |
| Bortle 7Suburban / urban transition | 4 h 45 min4,274 subs | 19 h17,094 subs | 76 h68,373 subs |
| Bortle 8City | 6 h 48 min6,119 subs | 27 h24,473 subs | 110+ h97,889 subs |
| Bortle 9Inner city | 11 h10,053 subs | 45 h40,210 subs | 180+ h160,837 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 18 h of run time. That is more than one night: over 3 nights, about 5 h 57 min each. The Odyssey’s battery is rated at about 5 h, less near freezing, so each night needs an external 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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Everything that fits the Odyssey →
How it frames
The California Nebula is 160′ × 40′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it is 4.8× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.
Filters
The California 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 California Nebula
A long, faint hydrogen streak near Menkib, nearly three degrees end to end. Needs a wide field and a dual-band filter; it is almost invisible in broadband.
NGC 1499 · Emission nebula in Perseus · magnitude 6.0 · 160′ × 40′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
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 California Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- California Nebula with the ZWO Seestar S50: 2 h from Bortle 6
- California Nebula with the ZWO Seestar S50 Pro: 2 h 15 min from Bortle 6
- California Nebula with the ZWO Seestar S30: 2 h 20 min from Bortle 6
- California Nebula with the ZWO Seestar S30 Pro: 2 h 25 min from Bortle 6
- California Nebula with the DwarfLab DWARF 3: 2 h 28 min from Bortle 6
- California Nebula with the DwarfLab DWARF mini: 1 h 58 min from Bortle 6
- California Nebula with the DwarfLab Draco: 1 h 35 min from Bortle 6
- California Nebula with the DwarfLab DWARF II: 11 h from Bortle 6
- California Nebula with the Vaonis Vespera II: 3 h 13 min from Bortle 6
- California Nebula with the Vaonis Vespera Pro: 7 h 14 min from Bortle 6
- California Nebula with the Vaonis Vespera 3: 3 h 05 min from Bortle 6
- California Nebula with the Vaonis Vespera Pro 2: 6 h 53 min from Bortle 6
- California Nebula with the Unistellar eQuinox 2: 2 h 57 min from Bortle 6
- California Nebula with the Celestron Origin: 51 min from Bortle 6
- California Nebula with the Celestron Origin Mark II: 1 h 10 min from Bortle 6
All telescopes for the California Nebula · All targets for the Odyssey