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

About 6 h 37 min of total integration for a solid image, or 26 h for a showpiece. A quick look takes 1 h 39 min.

How many subs is that on the Vespera II?

At the default 10 s sub length, 2,380 subs for a solid image from Bortle 6 and 850 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 37 min to 4 h.

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

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 6 h 37 min (2,380 subs of 10 s) for a solid image of the Cone and Christmas Tree. A quick look takes 1 h 39 min; a showpiece 26 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 22 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 70% of the frame’s short side.

Cone and Christmas Tree with the Vaonis Vespera II: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	29 min176 subs	1 h 57 min701 subs	7 h 47 min2,801 subs
Bortle 2Typical dark site	31 min188 subs	2 h 05 min752 subs	8 h 21 min3,007 subs
Bortle 3Rural	35 min213 subs	2 h 22 min850 subs	9 h 26 min3,397 subs
Bortle 4Rural / suburban transition	45 min272 subs	3 h 01 min1,086 subs	12 h4,343 subs
Bortle 5Suburban	1 h 01 min366 subs	4 h 03 min1,461 subs	16 h5,841 subs
Bortle 6Bright suburban	1 h 39 min595 subs	6 h 37 min2,380 subs	26 h9,518 subs
Bortle 7Suburban / urban transition	2 h 52 min1,033 subs	11 h4,131 subs	46 h16,524 subs
Bortle 8City	4 h 45 min1,713 subs	19 h6,851 subs	76 h27,402 subs
Bortle 9Inner city	8 h 47 min3,163 subs	35 h12,650 subs	140+ h50,600 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 8 h 36 min of run time. That is more than one night: over 2 nights, about 4 h 18 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 January night.)

USB-C PD power bank 20000mAh 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
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Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
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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 Cone and Christmas Tree is 60′ × 30′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 70% 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, no EQ mode. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	2 h 22 min850 subs	4 h 03 min1,461 subs	11 h4,131 subs
20 s	1 h 58 min354 subs	3 h 40 min659 subs	11 h1,994 subs
30 s	1 h 50 min220 subs	3 h 32 min424 subs	11 h1,314 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	2 h 22 min850 subs	4 h 03 min1,461 subs	11 h4,131 subs
dual-band (Dual Band filter), clip-on	2 h 42 min970 subs	3 h 13 min1,157 subs	5 h 29 min1,975 subs

The Vespera II has no built-in dual-band filter. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar; the app detects which is fitted. 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 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.

Where to buy the Vespera IIVaonis 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 Cone and Christmas Tree with your Vespera II? 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 II? 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 II