How long to image the Witch Head Nebula with the Vaonis Vespera II
From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 41 h (14,628 subs of 10 s) for a solid image of the Witch Head Nebula. A quick look takes 10 h; a showpiece 160+ h. Under a Bortle 3 rural sky the solid figure drops to 14 h. 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 2.1× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 2 h 48 min1,008 subs | 11 h4,032 subs | 45 h16,126 subs |
| Bortle 2Typical dark site | 3 h 02 min1,090 subs | 12 h4,357 subs | 48 h17,428 subs |
| Bortle 3Rural | 3 h 27 min1,244 subs | 14 h4,973 subs | 55 h19,890 subs |
| Bortle 4Rural / suburban transition | 4 h 29 min1,616 subs | 18 h6,464 subs | 72 h25,856 subs |
| Bortle 5Suburban | 6 h 08 min2,207 subs | 25 h8,828 subs | 98 h35,311 subs |
| Bortle 6Bright suburban | 10 h3,657 subs | 41 h14,628 subs | 160+ h58,510 subs |
| Bortle 7Suburban / urban transition | 18 h6,420 subs | 71 h25,679 subs | 290+ h102,714 subs |
| Bortle 8City | 30 h10,710 subs | 120+ h42,837 subs | 480+ h171,348 subs |
| Bortle 9Inner city | 55 h19,858 subs | 220+ h79,431 subs | 880+ h317,722 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 53 h of run time. That is more than one night: over 8 nights, about 6 h 36 min each. The Vespera II’s battery is rated at about 4 h, less near freezing, so each night needs an external power bank. (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 Witch Head Nebula is 180′ × 60′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it is 2.1× 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 | 14 h4,973 subs | 25 h8,828 subs | 71 h25,679 subs |
| 20 s | 11 h2,035 subs | 22 h3,963 subs | 69 h12,388 subs |
| 30 s | 10 h1,257 subs | 21 h2,542 subs | 68 h8,159 subs |
About the Witch Head Nebula
A very faint blue reflection nebula lit by Rigel. A dark-sky, all-night, broadband project; it is one of the hardest objects on this list.
IC 2118 · Reflection nebula in Eridanus · magnitude 13.0 · 180′ × 60′ · 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 Witch Head 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
- Witch Head Nebula with the ZWO Seestar S50: 41 h from Bortle 6
- Witch Head Nebula with the ZWO Seestar S50 Pro: 44 h from Bortle 6
- Witch Head Nebula with the ZWO Seestar S30: 43 h from Bortle 6
- Witch Head Nebula with the ZWO Seestar S30 Pro: 47 h from Bortle 6
- Witch Head Nebula with the DwarfLab DWARF 3: 59 h from Bortle 6
- Witch Head Nebula with the DwarfLab DWARF mini: 40 h from Bortle 6
- Witch Head Nebula with the DwarfLab Draco: 33 h from Bortle 6
- Witch Head Nebula with the DwarfLab DWARF II: 140+ h from Bortle 6
- Witch Head Nebula with the Vaonis Vespera Pro: 91 h from Bortle 6
- Witch Head Nebula with the Vaonis Vespera 3: 39 h from Bortle 6
- Witch Head Nebula with the Vaonis Vespera Pro 2: 87 h from Bortle 6
- Witch Head Nebula with the Unistellar eQuinox 2: 38 h from Bortle 6
- Witch Head Nebula with the Unistellar Odyssey: 180+ h from Bortle 6
- Witch Head Nebula with the Celestron Origin: 11 h from Bortle 6
- Witch Head Nebula with the Celestron Origin Mark II: 15 h from Bortle 6
All telescopes for the Witch Head Nebula · All targets for the Vespera II