How long to image the Little Dumbbell with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 45 min (272 subs of 10 s) for a solid image of the Little Dumbbell. A quick look takes 11 min; a showpiece 3 h 01 min. Under a Bortle 3 rural sky the solid figure drops to 20 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 3% 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 | 4 min27 subs | 18 min107 subs | 1 h 11 min427 subs |
| Bortle 2Typical dark site | 5 min28 subs | 19 min112 subs | 1 h 14 min447 subs |
| Bortle 3Rural | 5 min31 subs | 20 min122 subs | 1 h 21 min485 subs |
| Bortle 4Rural / suburban transition | 6 min37 subs | 24 min145 subs | 1 h 36 min578 subs |
| Bortle 5Suburban | 8 min46 subs | 30 min182 subs | 2 h 01 min725 subs |
| Bortle 6Bright suburban | 11 min68 subs | 45 min272 subs | 3 h 01 min1,086 subs |
| Bortle 7Suburban / urban transition | 18 min111 subs | 1 h 14 min444 subs | 4 h 56 min1,774 subs |
| Bortle 8City | 30 min178 subs | 1 h 58 min711 subs | 7 h 54 min2,843 subs |
| Bortle 9Inner city | 53 min321 subs | 3 h 33 min1,281 subs | 14 h5,121 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 59 min of run time. The Vespera II’s battery (rated about 4 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 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
- Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
- 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 II →
How it frames
The Little Dumbbell is 2.7′ × 1.8′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 3% 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 | 20 min122 subs | 30 min182 subs | 1 h 14 min444 subs |
| 20 s | 18 min54 subs | 28 min84 subs | 1 h 12 min215 subs |
| 30 s | 17 min35 subs | 27 min55 subs | 1 h 11 min142 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 20 min122 subs | 30 min182 subs | 1 h 14 min444 subs |
| dual-band (Dual Band filter), clip-on | 25 min150 subs | 28 min168 subs | 41 min248 subs |
The Vespera II has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted. On an emission target like this it is the single biggest upgrade you can make.
About the Little Dumbbell
A small, bright-per-pixel planetary in Perseus. Dual-band makes the two lobes and the faint wings much easier.
M76, NGC 650 · Planetary nebula in Perseus · magnitude 10.1 · 2.7′ × 1.8′ · best in Sep, Oct, Nov. 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 II
A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.
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; the app detects which is fitted.
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 Little Dumbbell from a Vespera II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Little Dumbbell with the ZWO Seestar S50: 33 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S50 Pro: 36 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S30: 37 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S30 Pro: 39 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF 3: 43 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF mini: 32 min from Bortle 6
- Little Dumbbell with the DwarfLab Draco: 26 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF II: 2 h 32 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera Pro: 1 h 41 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera 3: 43 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera Pro 2: 1 h 36 min from Bortle 6
- Little Dumbbell with the Unistellar eQuinox 2: 40 min from Bortle 6
- Little Dumbbell with the Unistellar Odyssey: 3 h 01 min from Bortle 6
- Little Dumbbell with the Celestron Origin: 12 min from Bortle 6
- Little Dumbbell with the Celestron Origin Mark II: 17 min from Bortle 6
All telescopes for the Little Dumbbell · All targets for the Vespera II