How long to image the Witch Head Nebula with the Vaonis Vespera Pro 2

From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 87 h (31,346 subs of 10 s) for a solid image of the Witch Head Nebula. A quick look takes 22 h; a showpiece 350+ h. Under a Bortle 3 rural sky the solid figure drops to 33 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 1.8× wider than the frame.

Witch Head Nebula with the Vaonis Vespera Pro 2: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site6 h 55 min2,488 subs28 h9,950 subs110+ h39,800 subs
Bortle 2Typical dark site7 h 22 min2,652 subs29 h10,608 subs120+ h42,429 subs
Bortle 3Rural8 h 14 min2,963 subs33 h11,851 subs130+ h47,401 subs
Bortle 4Rural / suburban transition10 h3,716 subs41 h14,862 subs170+ h59,447 subs
Bortle 5Suburban14 h4,909 subs55 h19,635 subs220+ h78,540 subs
Bortle 6Bright suburban22 h7,837 subs87 h31,346 subs350+ h125,384 subs
Bortle 7Suburban / urban transition37 h13,416 subs150+ h53,661 subs600+ h214,643 subs
Bortle 8City61 h22,077 subs250+ h88,308 subs980+ h353,230 subs
Bortle 9Inner city110+ h40,550 subs450+ h162,199 subs1800+ h648,795 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 110+ h of run time. That is more than one night: over 17 nights, about 6 h 40 min each. The Vespera Pro 2’s battery is rated at about 11 h, less near freezing, which is cutting it fine; take a power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a December night.)

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How it frames

The Witch Head Nebula is 180′ × 60′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it is 1.8× 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; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Time for a solid image by sub length:

Sub lengthBortle 3Bortle 5Bortle 7
10 s33 h11,851 subs55 h19,635 subs150+ h53,661 subs
20 s26 h4,747 subs48 h8,640 subs140+ h25,652 subs
30 s24 h2,903 subs46 h5,498 subs140+ h16,840 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 Pro 2

The square-sensor 2026 Vespera with 2 µm pixels. Sharper than the Vespera 3 on small targets and correspondingly slower per pixel; the 12.5 MP square frame suits galaxies and planetaries.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar.

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.

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Imaged the Witch Head Nebula with your Vespera Pro 2? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Witch Head Nebula from a Vespera Pro 2? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Witch Head Nebula · All targets for the Vespera Pro 2