How long should I image the Flaming Star Nebula with the Vespera 3 from a Bortle 6 sky?

About 2 h 35 min of total integration for a solid image, or 10 h for a showpiece. A quick look takes 39 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 928 subs for a solid image from Bortle 6 and 343 from Bortle 3.

Does a dual-band filter help on the Flaming Star Nebula?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 2 h 35 min to 1 h 35 min.

How long to image the Flaming Star Nebula with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 2 h 35 min (928 subs of 10 s) for a solid image of the Flaming Star Nebula. A quick look takes 39 min; a showpiece 10 h. Under a Bortle 3 rural sky the solid figure drops to 57 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 34% of the frame’s short side.

Flaming Star Nebula 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	12 min72 subs	48 min286 subs	3 h 10 min1,141 subs
Bortle 2Typical dark site	13 min77 subs	51 min305 subs	3 h 23 min1,220 subs
Bortle 3Rural	14 min86 subs	57 min343 subs	3 h 48 min1,369 subs
Bortle 4Rural / suburban transition	18 min109 subs	1 h 12 min433 subs	4 h 48 min1,731 subs
Bortle 5Suburban	24 min144 subs	1 h 36 min576 subs	6 h 24 min2,304 subs
Bortle 6Bright suburban	39 min232 subs	2 h 35 min928 subs	10 h3,709 subs
Bortle 7Suburban / urban transition	1 h 07 min400 subs	4 h 26 min1,597 subs	18 h6,388 subs
Bortle 8City	1 h 50 min660 subs	7 h 19 min2,637 subs	29 h10,547 subs
Bortle 9Inner city	3 h 22 min1,214 subs	13 h4,855 subs	54 h19,417 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 21 min of run time. The Vespera 3’s battery (rated about 11 h) should cover it; 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 December 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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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 Flaming Star Nebula is 30′ × 19′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 34% 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	57 min343 subs	1 h 36 min576 subs	4 h 26 min1,597 subs
20 s	48 min145 subs	1 h 27 min262 subs	4 h 17 min773 subs
30 s	45 min91 subs	1 h 24 min169 subs	4 h 14 min509 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	57 min343 subs	1 h 36 min576 subs	4 h 26 min1,597 subs
dual-band (Dual Band filter), clip-on	1 h 05 min393 subs	1 h 17 min465 subs	2 h 09 min777 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 Flaming Star Nebula

Emission and reflection lit by the runaway star AE Aurigae. Dual-band for the red; a broadband stack adds the blue.

IC 405, Caldwell 31 · Emission nebula in Auriga · magnitude 6.0 · 30′ × 19′ · best in Nov, Dec, Jan. 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 Flaming Star Nebula with your Vespera 3? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Flaming Star Nebula 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 Flaming Star Nebula · All targets for the Vespera 3