How long to image the Elephant's Trunk Nebula with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 3 h 51 min (1,388 subs of 10 s) for a solid image of the Elephant's Trunk Nebula. A quick look takes 58 min; a showpiece 15 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 25 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 is 2.0× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 18 min106 subs | 1 h 10 min422 subs | 4 h 41 min1,686 subs |
| Bortle 2Typical dark site | 19 min113 subs | 1 h 15 min452 subs | 5 h 01 min1,805 subs |
| Bortle 3Rural | 21 min127 subs | 1 h 25 min508 subs | 5 h 38 min2,029 subs |
| Bortle 4Rural / suburban transition | 27 min161 subs | 1 h 47 min644 subs | 7 h 09 min2,574 subs |
| Bortle 5Suburban | 36 min215 subs | 2 h 23 min859 subs | 9 h 33 min3,436 subs |
| Bortle 6Bright suburban | 58 min347 subs | 3 h 51 min1,388 subs | 15 h5,552 subs |
| Bortle 7Suburban / urban transition | 1 h 40 min599 subs | 6 h 39 min2,396 subs | 27 h9,583 subs |
| Bortle 8City | 2 h 45 min991 subs | 11 h3,961 subs | 44 h15,843 subs |
| Bortle 9Inner city | 5 h 04 min1,825 subs | 20 h7,298 subs | 81 h29,192 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 5 h 01 min of run time. The Vespera II’s battery is rated at about 4 h, so the session needs an external power bank. (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 Elephant's Trunk Nebula is 170′ × 140′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it is 2.0× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.
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 | 1 h 25 min508 subs | 2 h 23 min859 subs | 6 h 39 min2,396 subs |
| 20 s | 1 h 11 min213 subs | 2 h 09 min389 subs | 6 h 26 min1,157 subs |
| 30 s | 1 h 06 min133 subs | 2 h 05 min250 subs | 6 h 21 min762 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 1 h 25 min508 subs | 2 h 23 min859 subs | 6 h 39 min2,396 subs |
| dual-band (Dual Band filter), clip-on | 1 h 37 min585 subs | 1 h 55 min693 subs | 3 h 14 min1,163 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 Elephant's Trunk Nebula
A vast, faint hydrogen cloud in Cepheus with the dark trunk winding through it. Huge, so wide scopes frame the whole thing; dual-band is essential from any lit sky.
IC 1396 · Emission nebula in Cepheus · magnitude 3.5 · 170′ × 140′ · best in Jul, Aug, Sep. 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 Elephant's Trunk 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
- Elephant's Trunk Nebula with the ZWO Seestar S50: 2 h 22 min from Bortle 6
- Elephant's Trunk Nebula with the ZWO Seestar S50 Pro: 2 h 40 min from Bortle 6
- Elephant's Trunk Nebula with the ZWO Seestar S30: 2 h 47 min from Bortle 6
- Elephant's Trunk Nebula with the ZWO Seestar S30 Pro: 2 h 53 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab DWARF 3: 2 h 55 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab DWARF mini: 2 h 20 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab Draco: 1 h 52 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab DWARF II: 13 h from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera Pro: 8 h 39 min from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera 3: 3 h 41 min from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera Pro 2: 8 h 15 min from Bortle 6
- Elephant's Trunk Nebula with the Unistellar eQuinox 2: 3 h 32 min from Bortle 6
- Elephant's Trunk Nebula with the Unistellar Odyssey: 16 h from Bortle 6
- Elephant's Trunk Nebula with the Celestron Origin: 1 h 01 min from Bortle 6
- Elephant's Trunk Nebula with the Celestron Origin Mark II: 1 h 24 min from Bortle 6
All telescopes for the Elephant's Trunk Nebula · All targets for the Vespera II