How long to image the M72 with the Vaonis Vespera 3
From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 1 h 08 min (410 subs of 10 s) for a solid image of the M72. A quick look takes 17 min; a showpiece 4 h 33 min. Under a Bortle 3 rural sky the solid figure drops to 29 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 7% 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 | 6 min38 subs | 25 min150 subs | 1 h 40 min598 subs |
| Bortle 2Typical dark site | 7 min40 subs | 26 min158 subs | 1 h 45 min630 subs |
| Bortle 3Rural | 7 min44 subs | 29 min173 subs | 1 h 55 min690 subs |
| Bortle 4Rural / suburban transition | 9 min53 subs | 35 min210 subs | 2 h 19 min837 subs |
| Bortle 5Suburban | 11 min67 subs | 45 min268 subs | 2 h 58 min1,069 subs |
| Bortle 6Bright suburban | 17 min103 subs | 1 h 08 min410 subs | 4 h 33 min1,638 subs |
| Bortle 7Suburban / urban transition | 28 min171 subs | 1 h 53 min681 subs | 7 h 34 min2,723 subs |
| Bortle 8City | 46 min276 subs | 3 h 04 min1,102 subs | 12 h4,408 subs |
| Bortle 9Inner city | 1 h 23 min501 subs | 5 h 33 min2,001 subs | 22 h8,002 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 29 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.)
- 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.
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Everything that fits the Vespera 3 →
How it frames
The M72 is 6′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 7% 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 | 29 min173 subs | 45 min268 subs | 1 h 53 min681 subs |
| 20 s | 25 min76 subs | 41 min123 subs | 1 h 50 min330 subs |
| 30 s | 24 min49 subs | 40 min80 subs | 1 h 49 min218 subs |
About the M72
A faint, distant globular in Aquarius. Among the harder Messier globulars.
NGC 6981 · Globular cluster in Aquarius · magnitude 9.3 · 6′ · best in Jul, Aug, Sep. 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 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 M72 from a Vespera 3? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M72 with the ZWO Seestar S50: 1 h 11 min from Bortle 6
- M72 with the ZWO Seestar S50 Pro: 1 h 18 min from Bortle 6
- M72 with the ZWO Seestar S30: 1 h 15 min from Bortle 6
- M72 with the ZWO Seestar S30 Pro: 1 h 23 min from Bortle 6
- M72 with the DwarfLab DWARF 3: 1 h 44 min from Bortle 6
- M72 with the DwarfLab DWARF mini: 1 h 11 min from Bortle 6
- M72 with the DwarfLab Draco: 59 min from Bortle 6
- M72 with the DwarfLab DWARF II: 4 h 02 min from Bortle 6
- M72 with the Vaonis Vespera II: 1 h 11 min from Bortle 6
- M72 with the Vaonis Vespera Pro: 2 h 39 min from Bortle 6
- M72 with the Vaonis Vespera Pro 2: 2 h 32 min from Bortle 6
- M72 with the Unistellar eQuinox 2: 1 h 04 min from Bortle 6
- M72 with the Unistellar Odyssey: 4 h 51 min from Bortle 6
- M72 with the Celestron Origin: 19 min from Bortle 6
- M72 with the Celestron Origin Mark II: 26 min from Bortle 6