How long should I image the Cone and Christmas Tree with the Vespera Pro 2 from a Bortle 6 sky?

About 14 h of total integration for a solid image, or 57 h for a showpiece. A quick look takes 3 h 32 min.

How many subs is that on the Vespera Pro 2?

At the default 10 s sub length, 5,092 subs for a solid image from Bortle 6 and 2,002 from Bortle 3.

Does a dual-band filter help on the Cone and Christmas Tree?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 14 h to 9 h 42 min.

How long to image the Cone and Christmas Tree with the Vaonis Vespera Pro 2

From a Bortle 6 suburban sky, the Vaonis Vespera Pro 2 needs about 14 h (5,092 subs of 10 s) for a solid image of the Cone and Christmas Tree. A quick look takes 3 h 32 min; a showpiece 57 h. Under a Bortle 3 rural sky the solid figure drops to 5 h 34 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 60% of the frame’s short side.

Cone and Christmas Tree 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 11 min426 subs	4 h 43 min1,701 subs	19 h6,802 subs
Bortle 2Typical dark site	1 h 15 min452 subs	5 h 01 min1,805 subs	20 h7,218 subs
Bortle 3Rural	1 h 23 min501 subs	5 h 34 min2,002 subs	22 h8,006 subs
Bortle 4Rural / suburban transition	1 h 43 min620 subs	6 h 53 min2,479 subs	28 h9,916 subs
Bortle 5Suburban	2 h 15 min809 subs	8 h 59 min3,236 subs	36 h12,942 subs
Bortle 6Bright suburban	3 h 32 min1,273 subs	14 h5,092 subs	57 h20,366 subs
Bortle 7Suburban / urban transition	6 h2,158 subs	24 h8,629 subs	96 h34,513 subs
Bortle 8City	9 h 48 min3,530 subs	39 h14,120 subs	160+ h56,477 subs
Bortle 9Inner city	18 h6,458 subs	72 h25,831 subs	290+ h103,321 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 18 h of run time. That is more than one night: over 3 nights, about 6 h 08 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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How it frames

The Cone and Christmas Tree is 60′ × 30′ across. The Vespera Pro 2 frames 1.65° × 1.65° at 1.68″ per pixel, so it fills 60% 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	5 h 34 min2,002 subs	8 h 59 min3,236 subs	24 h8,629 subs
20 s	4 h 31 min814 subs	7 h 57 min1,431 subs	23 h4,128 subs
30 s	4 h 11 min502 subs	7 h 36 min913 subs	23 h2,711 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	5 h 34 min2,002 subs	8 h 59 min3,236 subs	24 h8,629 subs
dual-band (Dual Band filter), clip-on	7 h 04 min2,544 subs	8 h 07 min2,922 subs	13 h4,573 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 Cone and Christmas Tree

A bright cluster shaped like a tree with the faint Cone Nebula at its tip and the Fox Fur beside it. The cluster is easy; the nebulosity is not.

NGC 2264 · Emission nebula in Monoceros · magnitude 3.9 · 60′ × 30′ · 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.

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Imaged the Cone and Christmas Tree 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 Cone and Christmas Tree 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 Cone and Christmas Tree · All targets for the Vespera Pro 2