How long to image the De Mairan's Nebula with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 47 min (284 subs of 10 s) for a solid image of the De Mairan's Nebula. A quick look takes 12 min; a showpiece 3 h 09 min. Under a Bortle 3 rural sky the solid figure drops to 19 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 23% 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 min25 subs | 17 min100 subs | 1 h 06 min397 subs |
| Bortle 2Typical dark site | 4 min27 subs | 17 min105 subs | 1 h 10 min420 subs |
| Bortle 3Rural | 5 min29 subs | 19 min116 subs | 1 h 17 min463 subs |
| Bortle 4Rural / suburban transition | 6 min36 subs | 24 min142 subs | 1 h 34 min567 subs |
| Bortle 5Suburban | 8 min46 subs | 30 min183 subs | 2 h 02 min731 subs |
| Bortle 6Bright suburban | 12 min71 subs | 47 min284 subs | 3 h 09 min1,134 subs |
| Bortle 7Suburban / urban transition | 20 min119 subs | 1 h 19 min476 subs | 5 h 17 min1,902 subs |
| Bortle 8City | 32 min194 subs | 2 h 09 min774 subs | 8 h 36 min3,095 subs |
| Bortle 9Inner city | 59 min353 subs | 3 h 55 min1,410 subs | 16 h5,639 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 01 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, and 30% off the battery for a December night.)
- 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.
- hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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Everything that fits the Vespera II →
How it frames
The De Mairan's Nebula is 20′ × 15′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 23% 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 | 19 min116 subs | 30 min183 subs | 1 h 19 min476 subs |
| 20 s | 17 min50 subs | 28 min84 subs | 1 h 17 min230 subs |
| 30 s | 16 min32 subs | 27 min54 subs | 1 h 16 min152 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 19 min116 subs | 30 min183 subs | 1 h 19 min476 subs |
| dual-band (Dual Band filter), clip-on | 23 min139 subs | 26 min159 subs | 41 min249 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 De Mairan's Nebula
The comma-shaped nebula north of the Orion Nebula's core, split from it by a dark lane. Always in the same frame as M42.
M43, NGC 1982 · Emission nebula in Orion · magnitude 9.0 · 20′ × 15′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
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 De Mairan's Nebula from a Vespera II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- De Mairan's Nebula with the ZWO Seestar S50: 32 min from Bortle 6
- De Mairan's Nebula with the ZWO Seestar S50 Pro: 35 min from Bortle 6
- De Mairan's Nebula with the ZWO Seestar S30: 36 min from Bortle 6
- De Mairan's Nebula with the ZWO Seestar S30 Pro: 38 min from Bortle 6
- De Mairan's Nebula with the DwarfLab DWARF 3: 40 min from Bortle 6
- De Mairan's Nebula with the DwarfLab DWARF mini: 31 min from Bortle 6
- De Mairan's Nebula with the DwarfLab Draco: 25 min from Bortle 6
- De Mairan's Nebula with the DwarfLab DWARF II: 2 h 41 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera Pro: 1 h 46 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera 3: 45 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera Pro 2: 1 h 41 min from Bortle 6
- De Mairan's Nebula with the Unistellar eQuinox 2: 42 min from Bortle 6
- De Mairan's Nebula with the Unistellar Odyssey: 3 h 15 min from Bortle 6
- De Mairan's Nebula with the Celestron Origin: 13 min from Bortle 6
- De Mairan's Nebula with the Celestron Origin Mark II: 17 min from Bortle 6
All telescopes for the De Mairan's Nebula · All targets for the Vespera II