How long should I image the M79 with the Vespera 3 from a Bortle 6 sky?

About 15 min of total integration for a solid image, or 1 h 01 min for a showpiece. A quick look takes 4 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 92 subs for a solid image from Bortle 6 and 45 from Bortle 3.

Does a dual-band filter help on the M79?

No. The M79 is a broadband target and a dual-band filter blocks most of its light. Shoot without a filter.

How long to image the M79 with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 15 min (92 subs of 10 s) for a solid image of the M79. A quick look takes 4 min; a showpiece 1 h 01 min. Under a Bortle 3 rural sky the solid figure drops to 7 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 10% of the frame’s short side.

M79 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 min11 subs	7 min41 subs	27 min162 subs
Bortle 2Typical dark site	2 min11 subs	7 min42 subs	28 min168 subs
Bortle 3Rural	2 min12 subs	7 min45 subs	30 min180 subs
Bortle 4Rural / suburban transition	2 min14 subs	9 min53 subs	35 min209 subs
Bortle 5Suburban	3 min16 subs	11 min64 subs	42 min254 subs
Bortle 6Bright suburban	4 min23 subs	15 min92 subs	1 h 01 min366 subs
Bortle 7Suburban / urban transition	6 min37 subs	24 min145 subs	1 h 37 min580 subs
Bortle 8City	9 min57 subs	38 min228 subs	2 h 32 min911 subs
Bortle 9Inner city	17 min102 subs	1 h 07 min405 subs	4 h 30 min1,619 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 20 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 M79 is 9′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 10% 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	7 min45 subs	11 min64 subs	24 min145 subs
20 s	10 min30 subs	10 min30 subs	23 min71 subs
30 s	15 min30 subs	15 min30 subs	23 min47 subs

About the M79

A winter globular below Orion, unusual for the season. Low but compact.

NGC 1904 · Globular cluster in Lepus · magnitude 7.7 · 9′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.

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 M79 with your Vespera 3? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M79 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 M79 · All targets for the Vespera 3