How long should I image the Cone and Christmas Tree with the Vespera 3 from a Bortle 6 sky?

About 6 h 19 min of total integration for a solid image, or 25 h for a showpiece. A quick look takes 1 h 35 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 2,273 subs for a solid image from Bortle 6 and 803 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 6 h 19 min to 3 h 46 min.

How long to image the Cone and Christmas Tree with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 6 h 19 min (2,273 subs of 10 s) for a solid image of the Cone and Christmas Tree. A quick look takes 1 h 35 min; a showpiece 25 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 14 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 68% of the frame’s short side.

Cone and Christmas Tree with the Vaonis Vespera 3: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	27 min165 subs	1 h 50 min660 subs	7 h 19 min2,637 subs
Bortle 2Typical dark site	30 min178 subs	1 h 58 min709 subs	7 h 53 min2,836 subs
Bortle 3Rural	33 min201 subs	2 h 14 min803 subs	8 h 55 min3,210 subs
Bortle 4Rural / suburban transition	43 min258 subs	2 h 52 min1,030 subs	11 h4,119 subs
Bortle 5Suburban	58 min348 subs	3 h 52 min1,390 subs	15 h5,558 subs
Bortle 6Bright suburban	1 h 35 min569 subs	6 h 19 min2,273 subs	25 h9,089 subs
Bortle 7Suburban / urban transition	2 h 45 min989 subs	11 h3,955 subs	44 h15,817 subs
Bortle 8City	4 h 34 min1,642 subs	18 h6,566 subs	73 h26,264 subs
Bortle 9Inner city	8 h 26 min3,034 subs	34 h12,136 subs	130+ h48,544 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 8 h 12 min of run time. That is more than one night: over 2 nights, about 4 h 06 min each. The Vespera 3’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 30WVaonis says an external bank extends sessions; 30 W PD as for the II and Pro.
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How it frames

The Cone and Christmas Tree is 60′ × 30′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 68% 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 widens the field to 4.3° × 2.4°. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	2 h 14 min803 subs	3 h 52 min1,390 subs	11 h3,955 subs
20 s	1 h 52 min336 subs	3 h 30 min629 subs	11 h1,912 subs
30 s	1 h 44 min209 subs	3 h 22 min405 subs	10 h1,260 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	2 h 14 min803 subs	3 h 52 min1,390 subs	11 h3,955 subs
dual-band (Dual Band filter), clip-on	2 h 31 min905 subs	3 h 01 min1,085 subs	5 h 12 min1,870 subs

The Vespera 3 has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter. 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 3

The 2026 Vespera: same 50 mm quadruplet class as the II on an 8 MP IMX585, with a 24 MP mosaic mode and 11 hours of battery. Per pixel it behaves like a Seestar S50 Pro without the built-in dual-band filter.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only; CovalENS mosaic widens the field to 4.3° × 2.4°. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar. The new optical baffle is not a substitute for a CLS filter.

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 3? 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 3? 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 3