How long to image the Owl Nebula with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 54 min (322 subs of 10 s) for a solid image of the Owl Nebula. A quick look takes 13 min; a showpiece 3 h 34 min. Under a Bortle 3 rural sky the solid figure drops to 23 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 4% 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 | 5 min31 subs | 20 min123 subs | 1 h 22 min492 subs |
| Bortle 2Typical dark site | 5 min33 subs | 22 min130 subs | 1 h 26 min517 subs |
| Bortle 3Rural | 6 min36 subs | 23 min141 subs | 1 h 34 min563 subs |
| Bortle 4Rural / suburban transition | 7 min43 subs | 28 min169 subs | 1 h 52 min675 subs |
| Bortle 5Suburban | 9 min54 subs | 35 min213 subs | 2 h 22 min852 subs |
| Bortle 6Bright suburban | 13 min81 subs | 54 min322 subs | 3 h 34 min1,286 subs |
| Bortle 7Suburban / urban transition | 22 min133 subs | 1 h 28 min529 subs | 5 h 52 min2,113 subs |
| Bortle 8City | 35 min213 subs | 2 h 22 min850 subs | 9 h 26 min3,397 subs |
| Bortle 9Inner city | 1 h 04 min384 subs | 4 h 16 min1,535 subs | 17 h6,137 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 10 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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How it frames
The Owl Nebula is 3.4′ × 3.3′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 4% 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 | 23 min141 subs | 35 min213 subs | 1 h 28 min529 subs |
| 20 s | 21 min62 subs | 33 min98 subs | 1 h 25 min256 subs |
| 30 s | 20 min40 subs | 32 min64 subs | 1 h 24 min169 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 23 min141 subs | 35 min213 subs | 1 h 28 min529 subs |
| dual-band (Dual Band filter), clip-on | 29 min173 subs | 32 min195 subs | 48 min291 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 Owl Nebula
A round planetary with two dark eyes. Large for its class and low in surface brightness; dual-band helps a lot.
M97, NGC 3587 · Planetary nebula in Ursa Major · magnitude 9.9 · 3.4′ × 3.3′ · best in Feb, Mar, Apr. 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 Owl 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
- Owl Nebula with the ZWO Seestar S50: 38 min from Bortle 6
- Owl Nebula with the ZWO Seestar S50 Pro: 42 min from Bortle 6
- Owl Nebula with the ZWO Seestar S30: 43 min from Bortle 6
- Owl Nebula with the ZWO Seestar S30 Pro: 45 min from Bortle 6
- Owl Nebula with the DwarfLab DWARF 3: 49 min from Bortle 6
- Owl Nebula with the DwarfLab DWARF mini: 37 min from Bortle 6
- Owl Nebula with the DwarfLab Draco: 30 min from Bortle 6
- Owl Nebula with the DwarfLab DWARF II: 3 h from Bortle 6
- Owl Nebula with the Vaonis Vespera Pro: 1 h 59 min from Bortle 6
- Owl Nebula with the Vaonis Vespera 3: 51 min from Bortle 6
- Owl Nebula with the Vaonis Vespera Pro 2: 1 h 54 min from Bortle 6
- Owl Nebula with the Unistellar eQuinox 2: 47 min from Bortle 6
- Owl Nebula with the Unistellar Odyssey: 3 h 36 min from Bortle 6
- Owl Nebula with the Celestron Origin: 14 min from Bortle 6
- Owl Nebula with the Celestron Origin Mark II: 20 min from Bortle 6
All telescopes for the Owl Nebula · All targets for the Vespera II