How long to image the Double Cluster with the Vaonis Vespera 3
From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 5 min (30 subs of 10 s) for a solid image of the Double Cluster. A quick look takes 2 min; a showpiece 15 min. Under a Bortle 3 rural sky the solid figure drops to 5 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it fills 68% 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 | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 2Typical dark site | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 3Rural | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 4Rural / suburban transition | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 5Suburban | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 6Bright suburban | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 7Suburban / urban transition | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 8City | 2 min10 subs | 5 min32 subs | 21 min128 subs |
| Bortle 9Inner city | 2 min14 subs | 9 min55 subs | 36 min217 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 7 min of run time. The Vespera 3’s battery (rated about 11 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, and 30% off the battery for a November night.)
- USB-C PD power bank 20000mAh 30WVaonis says an external bank extends sessions; 30 W PD as for the II and Pro.
- 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 Vespera 3 →
How it frames
The Double Cluster is 60′ × 30′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 68% of the frame’s short side.
Longer subs
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic widens the field to 4.3° × 2.4°. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 5 min30 subs | 5 min30 subs | 5 min30 subs |
| 20 s | 10 min30 subs | 10 min30 subs | 10 min30 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 15 min30 subs |
About the Double Cluster
Two rich open clusters side by side in Perseus, naked-eye from a dark site. Short subs, short session, lovely result.
NGC 869 and NGC 884, Caldwell 14 · Open cluster in Perseus · magnitude 3.7 · 60′ × 30′ · best in Oct, Nov, Dec. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Open clusters are the easiest targets in the sky. The stars are bright, so the aim is colour and tight stars rather than depth: short subs, no filter, and stop before the bright members saturate. The nominal time here gets you clean star colour; more integration only adds background stars.
About the Vaonis Vespera 3
The 2026 Vespera: same 50 mm quadruplet class as the II on an 8 MP IMX585, with a 24 MP mosaic mode and 11 hours of battery. Per pixel it behaves like a Seestar S50 Pro without the built-in dual-band filter.
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic widens the field to 4.3° × 2.4°. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 10 s and 30 s subs is small; from a rural site it can halve the total time, especially with a dual-band filter in place.
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 Double Cluster from a Vespera 3? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Double Cluster with the ZWO Seestar S50: 5 min from Bortle 6
- Double Cluster with the ZWO Seestar S50 Pro: 5 min from Bortle 6
- Double Cluster with the ZWO Seestar S30: 5 min from Bortle 6
- Double Cluster with the ZWO Seestar S30 Pro: 5 min from Bortle 6
- Double Cluster with the DwarfLab DWARF 3: 8 min from Bortle 6
- Double Cluster with the DwarfLab DWARF mini: 8 min from Bortle 6
- Double Cluster with the DwarfLab Draco: 15 min from Bortle 6
- Double Cluster with the DwarfLab DWARF II: 8 min from Bortle 6
- Double Cluster with the Vaonis Vespera II: 5 min from Bortle 6
- Double Cluster with the Vaonis Vespera Pro: 6 min from Bortle 6
- Double Cluster with the Vaonis Vespera Pro 2: 5 min from Bortle 6
- Double Cluster with the Unistellar eQuinox 2: 2 min from Bortle 6
- Double Cluster with the Unistellar Odyssey: 9 min from Bortle 6
- Double Cluster with the Celestron Origin: 5 min from Bortle 6
- Double Cluster with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Double Cluster · All targets for the Vespera 3