How long to image the M18 with the Vaonis Vespera Pro
From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 9 min (57 subs of 10 s) for a solid image of the M18. A quick look takes 2 min; a showpiece 38 min. Under a Bortle 3 rural sky the solid figure drops to 6 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 9% 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 | 6 min34 subs | 22 min133 subs |
| Bortle 2Typical dark site | 2 min10 subs | 6 min34 subs | 23 min136 subs |
| Bortle 3Rural | 2 min10 subs | 6 min36 subs | 23 min141 subs |
| Bortle 4Rural / suburban transition | 2 min10 subs | 6 min39 subs | 26 min154 subs |
| Bortle 5Suburban | 2 min11 subs | 7 min44 subs | 29 min175 subs |
| Bortle 6Bright suburban | 2 min15 subs | 9 min57 subs | 38 min226 subs |
| Bortle 7Suburban / urban transition | 3 min21 subs | 13 min81 subs | 54 min324 subs |
| Bortle 8City | 5 min30 subs | 20 min119 subs | 1 h 19 min476 subs |
| Bortle 9Inner city | 8 min50 subs | 33 min200 subs | 2 h 13 min800 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 12 min of run time. The Vespera Pro’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 30WExtends the 11 h battery; 30 W PD per Vaonis.
- 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 →
How it frames
The M18 is 9′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it fills 9% 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, no EQ mode. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 6 min36 subs | 7 min44 subs | 13 min81 subs |
| 20 s | 10 min30 subs | 10 min30 subs | 13 min40 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 15 min30 subs |
About the M18
A small, sparse open cluster just south of the Omega Nebula. Usually caught in the same frame.
NGC 6613 · Open cluster in Sagittarius · magnitude 6.9 · 9′ · best in Jun, Jul, Aug. 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 Pro
The square-sensor Vespera with 2 µm pixels. Higher resolution than the II, and correspondingly slower per pixel: expect around double the time for the same per-pixel SNR. Run-out in 2026 and replaced by the Vespera Pro 2.
10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. 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 M18 from a Vespera Pro? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M18 with the ZWO Seestar S50: 5 min from Bortle 6
- M18 with the ZWO Seestar S50 Pro: 5 min from Bortle 6
- M18 with the ZWO Seestar S30: 5 min from Bortle 6
- M18 with the ZWO Seestar S30 Pro: 5 min from Bortle 6
- M18 with the DwarfLab DWARF 3: 8 min from Bortle 6
- M18 with the DwarfLab DWARF mini: 8 min from Bortle 6
- M18 with the DwarfLab Draco: 15 min from Bortle 6
- M18 with the DwarfLab DWARF II: 14 min from Bortle 6
- M18 with the Vaonis Vespera II: 5 min from Bortle 6
- M18 with the Vaonis Vespera 3: 5 min from Bortle 6
- M18 with the Vaonis Vespera Pro 2: 9 min from Bortle 6
- M18 with the Unistellar eQuinox 2: 3 min from Bortle 6
- M18 with the Unistellar Odyssey: 15 min from Bortle 6
- M18 with the Celestron Origin: 5 min from Bortle 6
- M18 with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the M18 · All targets for the Vespera Pro