How long to image the Hercules Cluster with the Vaonis Vespera Pro 2
From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 15 min (93 subs of 10 s) for a solid image of the Hercules Cluster. A quick look takes 4 min; a showpiece 1 h 02 min. Under a Bortle 3 rural sky the solid figure drops to 8 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 20% 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 min12 subs | 8 min46 subs | 30 min181 subs |
| Bortle 2Typical dark site | 2 min12 subs | 8 min47 subs | 31 min187 subs |
| Bortle 3Rural | 2 min13 subs | 8 min50 subs | 33 min198 subs |
| Bortle 4Rural / suburban transition | 2 min15 subs | 9 min57 subs | 37 min225 subs |
| Bortle 5Suburban | 3 min17 subs | 11 min67 subs | 45 min268 subs |
| Bortle 6Bright suburban | 4 min24 subs | 15 min93 subs | 1 h 02 min372 subs |
| Bortle 7Suburban / urban transition | 6 min36 subs | 24 min143 subs | 1 h 35 min570 subs |
| Bortle 8City | 9 min55 subs | 37 min220 subs | 2 h 26 min878 subs |
| Bortle 9Inner city | 16 min96 subs | 1 h 04 min384 subs | 4 h 16 min1,535 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 20 min of run time. The Vespera Pro 2’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.)
- USB-C PD power bank 20000mAh 30WExternal bank extends the 11 h battery.
- 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 Vespera Pro 2 →
How it frames
The Hercules Cluster is 20′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 20% 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 gives 3.2° × 3.2° at 50 MP. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 8 min50 subs | 11 min67 subs | 24 min143 subs |
| 20 s | 10 min30 subs | 10 min31 subs | 23 min69 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 23 min46 subs |
About the Hercules Cluster
The great northern globular, a few hundred thousand stars in a ball a third the Moon's width. Quick and always satisfying.
M13, NGC 6205 · Globular cluster in Hercules · magnitude 5.8 · 20′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
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 Vaonis Vespera Pro 2
The square-sensor 2026 Vespera with 2 µm pixels. Sharper than the Vespera 3 on small targets and correspondingly slower per pixel; the 12.5 MP square frame suits galaxies and planetaries.
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar.
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 Hercules Cluster from a Vespera Pro 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Hercules Cluster with the ZWO Seestar S50: 7 min from Bortle 6
- Hercules Cluster with the ZWO Seestar S50 Pro: 8 min from Bortle 6
- Hercules Cluster with the ZWO Seestar S30: 8 min from Bortle 6
- Hercules Cluster with the ZWO Seestar S30 Pro: 8 min from Bortle 6
- Hercules Cluster with the DwarfLab DWARF 3: 11 min from Bortle 6
- Hercules Cluster with the DwarfLab DWARF mini: 8 min from Bortle 6
- Hercules Cluster with the DwarfLab Draco: 15 min from Bortle 6
- Hercules Cluster with the DwarfLab DWARF II: 24 min from Bortle 6
- Hercules Cluster with the Vaonis Vespera II: 7 min from Bortle 6
- Hercules Cluster with the Vaonis Vespera Pro: 16 min from Bortle 6
- Hercules Cluster with the Vaonis Vespera 3: 7 min from Bortle 6
- Hercules Cluster with the Unistellar eQuinox 2: 6 min from Bortle 6
- Hercules Cluster with the Unistellar Odyssey: 28 min from Bortle 6
- Hercules Cluster with the Celestron Origin: 5 min from Bortle 6
- Hercules Cluster with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Hercules Cluster · All targets for the Vespera Pro 2