How long to image the NGC 6781 with the Vaonis Vespera Pro
From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 9 h 32 min (3,432 subs of 10 s) for a solid image of the NGC 6781. A quick look takes 2 h 23 min; a showpiece 38 h. Under a Bortle 3 rural sky the solid figure drops to 4 h. 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 2% 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 | 52 min311 subs | 3 h 27 min1,243 subs | 14 h4,972 subs |
| Bortle 2Typical dark site | 55 min328 subs | 3 h 38 min1,311 subs | 15 h5,241 subs |
| Bortle 3Rural | 1 h360 subs | 4 h1,438 subs | 16 h5,750 subs |
| Bortle 4Rural / suburban transition | 1 h 13 min437 subs | 4 h 51 min1,746 subs | 19 h6,982 subs |
| Bortle 5Suburban | 1 h 33 min559 subs | 6 h 12 min2,234 subs | 25 h8,934 subs |
| Bortle 6Bright suburban | 2 h 23 min858 subs | 9 h 32 min3,432 subs | 38 h13,725 subs |
| Bortle 7Suburban / urban transition | 3 h 58 min1,429 subs | 16 h5,714 subs | 63 h22,853 subs |
| Bortle 8City | 6 h 26 min2,315 subs | 26 h9,257 subs | 100+ h37,026 subs |
| Bortle 9Inner city | 12 h4,204 subs | 47 h16,813 subs | 190+ h67,252 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 12 h of run time. That is more than one night: over 2 nights, about 6 h 12 min each. The Vespera Pro’s battery (rated about 11 h) should cover each night; 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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How it frames
The NGC 6781 is 1.8′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it fills 2% 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 | 4 h1,438 subs | 6 h 12 min2,234 subs | 16 h5,714 subs |
| 20 s | 3 h 18 min594 subs | 5 h 30 min992 subs | 15 h2,732 subs |
| 30 s | 3 h 04 min368 subs | 5 h 16 min633 subs | 15 h1,793 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 4 h1,438 subs | 6 h 12 min2,234 subs | 16 h5,714 subs |
| dual-band (Dual Band filter), clip-on | 5 h 11 min1,866 subs | 5 h 52 min2,110 subs | 8 h 49 min3,175 subs |
The Vespera Pro has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. On an emission target like this it is the single biggest upgrade you can make.
About the NGC 6781
A ghostly ring planetary in Aquila, larger and fainter than the Ring Nebula. Dual-band recommended.
Aquila planetary · Planetary nebula in Aquila · magnitude 11.4 · 1.8′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
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 NGC 6781 from a Vespera Pro? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- NGC 6781 with the ZWO Seestar S50: 2 h 42 min from Bortle 6
- NGC 6781 with the ZWO Seestar S50 Pro: 3 h 02 min from Bortle 6
- NGC 6781 with the ZWO Seestar S30: 3 h 09 min from Bortle 6
- NGC 6781 with the ZWO Seestar S30 Pro: 3 h 16 min from Bortle 6
- NGC 6781 with the DwarfLab DWARF 3: 3 h 22 min from Bortle 6
- NGC 6781 with the DwarfLab DWARF mini: 2 h 40 min from Bortle 6
- NGC 6781 with the DwarfLab Draco: 2 h 08 min from Bortle 6
- NGC 6781 with the DwarfLab DWARF II: 15 h from Bortle 6
- NGC 6781 with the Vaonis Vespera II: 4 h 15 min from Bortle 6
- NGC 6781 with the Vaonis Vespera 3: 4 h 04 min from Bortle 6
- NGC 6781 with the Vaonis Vespera Pro 2: 9 h 05 min from Bortle 6
- NGC 6781 with the Unistellar eQuinox 2: 3 h 52 min from Bortle 6
- NGC 6781 with the Unistellar Odyssey: 18 h from Bortle 6
- NGC 6781 with the Celestron Origin: 1 h 07 min from Bortle 6
- NGC 6781 with the Celestron Origin Mark II: 1 h 33 min from Bortle 6
All telescopes for the NGC 6781 · All targets for the Vespera Pro