How long to image the Centaurus A with the Unistellar Odyssey
From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 2 h 49 min (2,532 subs of 4 s) for a solid image of the Centaurus A. A quick look takes 42 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 54 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 77% 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 | 27 min409 subs | 1 h 49 min1,633 subs | 7 h 15 min6,532 subs |
| Bortle 2Typical dark site | 28 min416 subs | 1 h 51 min1,661 subs | 7 h 23 min6,642 subs |
| Bortle 3Rural | 29 min429 subs | 1 h 54 min1,713 subs | 7 h 37 min6,851 subs |
| Bortle 4Rural / suburban transition | 31 min460 subs | 2 h 03 min1,840 subs | 8 h 10 min7,357 subs |
| Bortle 5Suburban | 34 min510 subs | 2 h 16 min2,040 subs | 9 h 04 min8,158 subs |
| Bortle 6Bright suburban | 42 min633 subs | 2 h 49 min2,532 subs | 11 h10,125 subs |
| Bortle 7Suburban / urban transition | 58 min868 subs | 3 h 51 min3,469 subs | 15 h13,873 subs |
| Bortle 8City | 1 h 22 min1,231 subs | 5 h 28 min4,923 subs | 22 h19,692 subs |
| Bortle 9Inner city | 2 h 14 min2,007 subs | 8 h 55 min8,026 subs | 36 h32,102 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 39 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 Centaurus A is 26′ × 20′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 77% of the frame’s short side.
About the Centaurus A
A giant elliptical with a thick dust band across it, the brightest radio galaxy in the sky. A southern-hemisphere showpiece.
NGC 5128, Caldwell 77 · Galaxy in Centaurus · magnitude 6.8 · 26′ × 20′ · best in Mar, Apr, May. Low or below the horizon from northern Europe; best from the southern US southwards.
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 Centaurus A from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Centaurus A with the ZWO Seestar S50: 41 min from Bortle 6
- Centaurus A with the ZWO Seestar S50 Pro: 45 min from Bortle 6
- Centaurus A with the ZWO Seestar S30: 43 min from Bortle 6
- Centaurus A with the ZWO Seestar S30 Pro: 48 min from Bortle 6
- Centaurus A with the DwarfLab DWARF 3: 1 h from Bortle 6
- Centaurus A with the DwarfLab DWARF mini: 41 min from Bortle 6
- Centaurus A with the DwarfLab Draco: 34 min from Bortle 6
- Centaurus A with the DwarfLab DWARF II: 2 h 19 min from Bortle 6
- Centaurus A with the Vaonis Vespera II: 41 min from Bortle 6
- Centaurus A with the Vaonis Vespera Pro: 1 h 32 min from Bortle 6
- Centaurus A with the Vaonis Vespera 3: 39 min from Bortle 6
- Centaurus A with the Vaonis Vespera Pro 2: 1 h 27 min from Bortle 6
- Centaurus A with the Unistellar eQuinox 2: 37 min from Bortle 6
- Centaurus A with the Celestron Origin: 11 min from Bortle 6
- Centaurus A with the Celestron Origin Mark II: 15 min from Bortle 6
All telescopes for the Centaurus A · All targets for the Odyssey