How long to image the 47 Tucanae with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 7 min (105 subs of 4 s) for a solid image of the 47 Tucanae. A quick look takes 2 min; a showpiece 28 min. Under a Bortle 3 rural sky the solid figure drops to 5 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it only just fits, at 92% of the short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 1 min20 subs | 5 min77 subs | 20 min307 subs |
| Bortle 2Typical dark site | 1 min20 subs | 5 min78 subs | 21 min310 subs |
| Bortle 3Rural | 1 min20 subs | 5 min80 subs | 21 min317 subs |
| Bortle 4Rural / suburban transition | 1 min21 subs | 6 min83 subs | 22 min332 subs |
| Bortle 5Suburban | 1 min23 subs | 6 min90 subs | 24 min357 subs |
| Bortle 6Bright suburban | 2 min27 subs | 7 min105 subs | 28 min419 subs |
| Bortle 7Suburban / urban transition | 2 min34 subs | 9 min134 subs | 36 min535 subs |
| Bortle 8City | 3 min45 subs | 12 min180 subs | 48 min717 subs |
| Bortle 9Inner city | 5 min69 subs | 18 min276 subs | 1 h 14 min1,103 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 9 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 47 Tucanae is 31′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it only just fits, at 92% of the short side. Centre it carefully: there is no room to crop back afterwards.
About the 47 Tucanae
The second-brightest globular, with a blazing core, next to the Small Magellanic Cloud. Far southern sky only.
NGC 104, Caldwell 106 · Globular cluster in Tucana · magnitude 4.0 · 31′ · best in Sep, Oct, Nov. Southern hemisphere only.
Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.
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 47 Tucanae from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- 47 Tucanae with the ZWO Seestar S50: 5 min from Bortle 6
- 47 Tucanae with the ZWO Seestar S50 Pro: 5 min from Bortle 6
- 47 Tucanae with the ZWO Seestar S30: 5 min from Bortle 6
- 47 Tucanae with the ZWO Seestar S30 Pro: 5 min from Bortle 6
- 47 Tucanae with the DwarfLab DWARF 3: 8 min from Bortle 6
- 47 Tucanae with the DwarfLab DWARF mini: 8 min from Bortle 6
- 47 Tucanae with the DwarfLab Draco: 15 min from Bortle 6
- 47 Tucanae with the DwarfLab DWARF II: 8 min from Bortle 6
- 47 Tucanae with the Vaonis Vespera II: 5 min from Bortle 6
- 47 Tucanae with the Vaonis Vespera Pro: 5 min from Bortle 6
- 47 Tucanae with the Vaonis Vespera 3: 5 min from Bortle 6
- 47 Tucanae with the Vaonis Vespera Pro 2: 5 min from Bortle 6
- 47 Tucanae with the Unistellar eQuinox 2: 2 min from Bortle 6
- 47 Tucanae with the Celestron Origin: 5 min from Bortle 6
- 47 Tucanae with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the 47 Tucanae · All targets for the Odyssey