How long should I image the Thor's Helmet with the Vespera Pro 2 from a Bortle 6 sky?

About 22 h of total integration for a solid image, or 89 h for a showpiece. A quick look takes 5 h 32 min.

How many subs is that on the Vespera Pro 2?

At the default 10 s sub length, 7,972 subs for a solid image from Bortle 6 and 3,153 from Bortle 3.

Does a dual-band filter help on the Thor's Helmet?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 22 h to 15 h.

How long to image the Thor's Helmet with the Vaonis Vespera Pro 2

From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 22 h (7,972 subs of 10 s) for a solid image of the Thor's Helmet. A quick look takes 5 h 32 min; a showpiece 89 h. Under a Bortle 3 rural sky the solid figure drops to 8 h 45 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 8% of the frame’s short side.

Thor's Helmet with the Vaonis Vespera Pro 2: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	1 h 52 min671 subs	7 h 27 min2,683 subs	30 h10,731 subs
Bortle 2Typical dark site	1 h 59 min712 subs	7 h 54 min2,846 subs	32 h11,381 subs
Bortle 3Rural	2 h 11 min789 subs	8 h 45 min3,153 subs	35 h12,610 subs
Bortle 4Rural / suburban transition	2 h 42 min975 subs	11 h3,897 subs	43 h15,587 subs
Bortle 5Suburban	3 h 32 min1,270 subs	14 h5,077 subs	56 h20,306 subs
Bortle 6Bright suburban	5 h 32 min1,993 subs	22 h7,972 subs	89 h31,885 subs
Bortle 7Suburban / urban transition	9 h 22 min3,372 subs	37 h13,487 subs	150+ h53,947 subs
Bortle 8City	15 h5,513 subs	61 h22,051 subs	250+ h88,202 subs
Bortle 9Inner city	28 h10,079 subs	110+ h40,315 subs	450+ h161,258 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 29 h of run time. That is more than one night: over 5 nights, about 5 h 45 min each. The Vespera Pro 2’s battery (rated about 11 h) should cover each night; 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 January night.)

USB-C PD power bank 20000mAh 30WExternal bank extends the 11 h battery.
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red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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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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How it frames

The Thor's Helmet is 8′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 8% 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; CovalENS mosaic gives 3.2° × 3.2° at 50 MP. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	8 h 45 min3,153 subs	14 h5,077 subs	37 h13,487 subs
20 s	7 h 08 min1,285 subs	12 h2,247 subs	36 h6,453 subs
30 s	6 h 36 min792 subs	12 h1,434 subs	35 h4,237 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	8 h 45 min3,153 subs	14 h5,077 subs	37 h13,487 subs
dual-band (Dual Band filter), clip-on	11 h4,011 subs	13 h4,600 subs	20 h7,175 subs

The Vespera Pro 2 has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. On an emission target like this it is the single biggest upgrade you can make.

About the Thor's Helmet

A Wolf-Rayet bubble with wings, strong in OIII. Small and faint; dual-band is essential and a bigger scope helps.

NGC 2359 · Emission nebula in Canis Major · magnitude 11.5 · 8′ · best in Dec, Jan, Feb. 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 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.

Where to buy the Vespera Pro 2Vaonis store Direct Amazon UK Amazon USThe Vaonis store link is a plain link; the others are affiliate links. As an Amazon Associate I earn from qualifying purchases, at no cost to you.

Imaged the Thor's Helmet 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 Thor's Helmet 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 Thor's Helmet · All targets for the Vespera Pro 2