How long to image the M78 with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 1 h 03 min (377 subs of 10 s) for a solid image of the M78. A quick look takes 16 min; a showpiece 4 h 11 min. Under a Bortle 3 rural sky the solid figure drops to 26 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 | 6 min35 subs | 23 min138 subs | 1 h 32 min551 subs |
| Bortle 2Typical dark site | 6 min37 subs | 24 min145 subs | 1 h 37 min580 subs |
| Bortle 3Rural | 7 min40 subs | 26 min159 subs | 1 h 46 min636 subs |
| Bortle 4Rural / suburban transition | 8 min49 subs | 32 min193 subs | 2 h 08 min770 subs |
| Bortle 5Suburban | 10 min62 subs | 41 min246 subs | 2 h 44 min983 subs |
| Bortle 6Bright suburban | 16 min95 subs | 1 h 03 min377 subs | 4 h 11 min1,506 subs |
| Bortle 7Suburban / urban transition | 26 min157 subs | 1 h 44 min626 subs | 6 h 57 min2,503 subs |
| Bortle 8City | 42 min254 subs | 2 h 49 min1,013 subs | 11 h4,050 subs |
| Bortle 9Inner city | 1 h 17 min460 subs | 5 h 06 min1,838 subs | 20 h7,349 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 22 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 M78 is 8′ × 6′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ 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 | 26 min159 subs | 41 min246 subs | 1 h 44 min626 subs |
| 20 s | 23 min70 subs | 38 min113 subs | 1 h 41 min303 subs |
| 30 s | 22 min44 subs | 36 min73 subs | 1 h 40 min200 subs |
About the M78
The brightest reflection nebula in the sky, blue dust lit by young stars in Orion's belt. No filter; it is starlight.
NGC 2068 · Reflection nebula in Orion · magnitude 8.3 · 8′ × 6′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Reflection nebulae are starlight scattered by dust, so they are broadband and blue. A dual-band filter removes almost all of it; do not use one. These are among the faintest structures a smart scope can attempt and the figures run long. A dark sky matters more here than for any other type, and the Moon must be down.
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 M78 from a Vespera II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M78 with the ZWO Seestar S50: 1 h 03 min from Bortle 6
- M78 with the ZWO Seestar S50 Pro: 1 h 09 min from Bortle 6
- M78 with the ZWO Seestar S30: 1 h 06 min from Bortle 6
- M78 with the ZWO Seestar S30 Pro: 1 h 13 min from Bortle 6
- M78 with the DwarfLab DWARF 3: 1 h 31 min from Bortle 6
- M78 with the DwarfLab DWARF mini: 1 h 02 min from Bortle 6
- M78 with the DwarfLab Draco: 52 min from Bortle 6
- M78 with the DwarfLab DWARF II: 3 h 32 min from Bortle 6
- M78 with the Vaonis Vespera Pro: 2 h 20 min from Bortle 6
- M78 with the Vaonis Vespera 3: 1 h from Bortle 6
- M78 with the Vaonis Vespera Pro 2: 2 h 13 min from Bortle 6
- M78 with the Unistellar eQuinox 2: 56 min from Bortle 6
- M78 with the Unistellar Odyssey: 4 h 16 min from Bortle 6
- M78 with the Celestron Origin: 17 min from Bortle 6
- M78 with the Celestron Origin Mark II: 23 min from Bortle 6