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

About 45 min of total integration for a solid image, or 3 h for a showpiece. A quick look takes 11 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 270 subs for a solid image from Bortle 6 and 115 from Bortle 3.

Does a dual-band filter help on the Sombrero Galaxy?

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

How long to image the Sombrero Galaxy with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 45 min (270 subs of 10 s) for a solid image of the Sombrero Galaxy. A quick look takes 11 min; a showpiece 3 h. Under a Bortle 3 rural sky the solid figure drops to 19 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.

Sombrero Galaxy 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	4 min25 subs	17 min100 subs	1 h 07 min400 subs
Bortle 2Typical dark site	4 min27 subs	18 min106 subs	1 h 10 min421 subs
Bortle 3Rural	5 min29 subs	19 min115 subs	1 h 17 min460 subs
Bortle 4Rural / suburban transition	6 min35 subs	23 min139 subs	1 h 33 min556 subs
Bortle 5Suburban	7 min45 subs	29 min177 subs	1 h 58 min707 subs
Bortle 6Bright suburban	11 min68 subs	45 min270 subs	3 h1,078 subs
Bortle 7Suburban / urban transition	19 min112 subs	1 h 14 min447 subs	4 h 58 min1,786 subs
Bortle 8City	30 min181 subs	2 h722 subs	8 h 01 min2,885 subs
Bortle 9Inner city	54 min327 subs	3 h 38 min1,307 subs	15 h5,228 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 58 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 Sombrero Galaxy is 9′ × 4′ 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	19 min115 subs	29 min177 subs	1 h 14 min447 subs
20 s	17 min51 subs	27 min82 subs	1 h 12 min217 subs
30 s	16 min33 subs	26 min53 subs	1 h 11 min143 subs

About the Sombrero Galaxy

The bright bulge and knife-edge dust lane are obvious within an hour. Low from northern Europe, so catch it near the meridian.

M104, NGC 4594 · Galaxy in Virgo · magnitude 8.0 · 9′ × 4′ · best in Mar, Apr, May. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.

Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.

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

Have an image of the Sombrero Galaxy 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 Sombrero Galaxy · All targets for the Vespera 3