How long to image the Pinwheel Galaxy with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 20 h (17,741 subs of 4 s) for a solid image of the Pinwheel Galaxy. A quick look takes 4 h 56 min; a showpiece 79 h. Under a Bortle 3 rural sky the solid figure drops to 13 h. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 86% 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 | 3 h 06 min2,789 subs | 12 h11,154 subs | 50 h44,616 subs |
| Bortle 2Typical dark site | 3 h 09 min2,840 subs | 13 h11,357 subs | 50 h45,425 subs |
| Bortle 3Rural | 3 h 16 min2,935 subs | 13 h11,739 subs | 52 h46,956 subs |
| Bortle 4Rural / suburban transition | 3 h 31 min3,167 subs | 14 h12,667 subs | 56 h50,665 subs |
| Bortle 5Suburban | 3 h 56 min3,534 subs | 16 h14,136 subs | 63 h56,542 subs |
| Bortle 6Bright suburban | 4 h 56 min4,436 subs | 20 h17,741 subs | 79 h70,963 subs |
| Bortle 7Suburban / urban transition | 6 h 50 min6,153 subs | 27 h24,611 subs | 110+ h98,441 subs |
| Bortle 8City | 9 h 48 min8,820 subs | 39 h35,277 subs | 160+ h141,105 subs |
| Bortle 9Inner city | 16 h14,506 subs | 64 h58,024 subs | 260+ h232,093 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 26 h of run time. That is more than one night: over 4 nights, about 6 h 24 min each. The Odyssey’s battery is rated at about 5 h, so each night needs an external power bank. (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 Pinwheel Galaxy is 29′ × 27′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 86% of the frame’s short side.
About the Pinwheel Galaxy
Big, face-on and faint. Its total magnitude is flattering; spread over half a degree the arms are dim and demand hours, especially from suburban skies.
M101, NGC 5457 · Galaxy in Ursa Major · magnitude 7.9 · 29′ × 27′ · best in Apr, May, Jun. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.
Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.
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 Pinwheel Galaxy from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Pinwheel Galaxy with the ZWO Seestar S50: 4 h 37 min from Bortle 6
- Pinwheel Galaxy with the ZWO Seestar S50 Pro: 5 h 03 min from Bortle 6
- Pinwheel Galaxy with the ZWO Seestar S30: 4 h 51 min from Bortle 6
- Pinwheel Galaxy with the ZWO Seestar S30 Pro: 5 h 21 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab DWARF 3: 6 h 41 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab DWARF mini: 4 h 35 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab Draco: 3 h 47 min from Bortle 6
- Pinwheel Galaxy with the DwarfLab DWARF II: 16 h from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera II: 4 h 37 min from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera Pro: 10 h from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera 3: 4 h 24 min from Bortle 6
- Pinwheel Galaxy with the Vaonis Vespera Pro 2: 9 h 52 min from Bortle 6
- Pinwheel Galaxy with the Unistellar eQuinox 2: 4 h 14 min from Bortle 6
- Pinwheel Galaxy with the Celestron Origin: 1 h 13 min from Bortle 6
- Pinwheel Galaxy with the Celestron Origin Mark II: 1 h 40 min from Bortle 6
All telescopes for the Pinwheel Galaxy · All targets for the Odyssey