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

About 12 min of total integration for a solid image, or 47 min for a showpiece. A quick look takes 3 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 71 subs for a solid image from Bortle 6 and 38 from Bortle 3.

Does a dual-band filter help on the Turtle Nebula?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 12 min to 10 min.

How long to image the Turtle Nebula with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 12 min (71 subs of 10 s) for a solid image of the Turtle Nebula. A quick look takes 3 min; a showpiece 47 min. Under a Bortle 3 rural sky the solid figure drops to 6 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 is small in the frame, about 7 pixels across.

Turtle 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	2 min10 subs	6 min35 subs	23 min139 subs
Bortle 2Typical dark site	2 min10 subs	6 min36 subs	24 min143 subs
Bortle 3Rural	2 min10 subs	6 min38 subs	25 min152 subs
Bortle 4Rural / suburban transition	2 min11 subs	7 min43 subs	29 min172 subs
Bortle 5Suburban	2 min13 subs	9 min52 subs	34 min205 subs
Bortle 6Bright suburban	3 min18 subs	12 min71 subs	47 min284 subs
Bortle 7Suburban / urban transition	5 min28 subs	18 min109 subs	1 h 12 min435 subs
Bortle 8City	7 min42 subs	28 min168 subs	1 h 52 min670 subs
Bortle 9Inner city	12 min74 subs	49 min293 subs	3 h 15 min1,172 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 15 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.)

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 Turtle Nebula is 0.3′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it is small in the frame, about 7 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.

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	6 min38 subs	9 min52 subs	18 min109 subs
20 s	10 min30 subs	10 min30 subs	18 min53 subs
30 s	15 min30 subs	15 min30 subs	17 min35 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	6 min38 subs	9 min52 subs	18 min109 subs
dual-band (Dual Band filter), clip-on	8 min49 subs	9 min53 subs	12 min71 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 Turtle Nebula

A tiny, very bright planetary in Hercules. A blue-green star-like blob in a smart scope, but an easy catch.

NGC 6210 · Planetary nebula in Hercules · magnitude 9.0 · 0.3′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.

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.

Where to buy the Vespera 3Vaonis 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 Turtle 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 Turtle 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 Turtle Nebula · All targets for the Vespera 3