How long to image the Lagoon Nebula with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 1 h 55 min (1,719 subs of 4 s) for a solid image of the Lagoon Nebula. A quick look takes 29 min; a showpiece 7 h 38 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 18 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is 2.7× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 19 min280 subs | 1 h 15 min1,119 subs | 4 h 58 min4,473 subs |
| Bortle 2Typical dark site | 19 min285 subs | 1 h 16 min1,137 subs | 5 h 03 min4,547 subs |
| Bortle 3Rural | 20 min293 subs | 1 h 18 min1,172 subs | 5 h 12 min4,687 subs |
| Bortle 4Rural / suburban transition | 21 min315 subs | 1 h 24 min1,257 subs | 5 h 35 min5,025 subs |
| Bortle 5Suburban | 23 min348 subs | 1 h 33 min1,391 subs | 6 h 11 min5,561 subs |
| Bortle 6Bright suburban | 29 min430 subs | 1 h 55 min1,719 subs | 7 h 38 min6,876 subs |
| Bortle 7Suburban / urban transition | 39 min587 subs | 2 h 36 min2,346 subs | 10 h9,382 subs |
| Bortle 8City | 55 min830 subs | 3 h 41 min3,319 subs | 15 h13,273 subs |
| Bortle 9Inner city | 1 h 30 min1,349 subs | 6 h5,393 subs | 24 h21,571 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 29 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 Lagoon Nebula is 90′ × 40′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it is 2.7× 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 Lagoon 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 Lagoon Nebula
The showpiece emission nebula of the summer Milky Way, bright enough to catch its core in minutes. Pair it with the Trifid in one wide frame.
M8, NGC 6523 · Emission nebula in Sagittarius · magnitude 6.0 · 90′ × 40′ · best in Jun, Jul, Aug. 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 Lagoon Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Lagoon Nebula with the ZWO Seestar S50: 20 min from Bortle 6
- Lagoon Nebula with the ZWO Seestar S50 Pro: 22 min from Bortle 6
- Lagoon Nebula with the ZWO Seestar S30: 22 min from Bortle 6
- Lagoon Nebula with the ZWO Seestar S30 Pro: 24 min from Bortle 6
- Lagoon Nebula with the DwarfLab DWARF 3: 25 min from Bortle 6
- Lagoon Nebula with the DwarfLab DWARF mini: 19 min from Bortle 6
- Lagoon Nebula with the DwarfLab Draco: 16 min from Bortle 6
- Lagoon Nebula with the DwarfLab DWARF II: 1 h 35 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera II: 28 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera Pro: 1 h 03 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera 3: 27 min from Bortle 6
- Lagoon Nebula with the Vaonis Vespera Pro 2: 1 h from Bortle 6
- Lagoon Nebula with the Unistellar eQuinox 2: 25 min from Bortle 6
- Lagoon Nebula with the Celestron Origin: 7 min from Bortle 6
- Lagoon Nebula with the Celestron Origin Mark II: 10 min from Bortle 6
All telescopes for the Lagoon Nebula · All targets for the Odyssey