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

About 4 h 24 min of total integration for a solid image, or 18 h for a showpiece. A quick look takes 1 h 06 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 1,586 subs for a solid image from Bortle 6 and 569 from Bortle 3.

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

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

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

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 4 h 24 min (1,586 subs of 10 s) for a solid image of the Pinwheel Galaxy. A quick look takes 1 h 06 min; a showpiece 18 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 35 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 33% of the frame’s short side.

Pinwheel 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	20 min118 subs	1 h 18 min470 subs	5 h 13 min1,879 subs
Bortle 2Typical dark site	21 min126 subs	1 h 24 min504 subs	5 h 36 min2,016 subs
Bortle 3Rural	24 min143 subs	1 h 35 min569 subs	6 h 19 min2,276 subs
Bortle 4Rural / suburban transition	30 min182 subs	2 h 01 min726 subs	8 h 04 min2,904 subs
Bortle 5Suburban	41 min244 subs	2 h 42 min975 subs	11 h3,900 subs
Bortle 6Bright suburban	1 h 06 min397 subs	4 h 24 min1,586 subs	18 h6,343 subs
Bortle 7Suburban / urban transition	1 h 55 min688 subs	7 h 38 min2,750 subs	31 h10,998 subs
Bortle 8City	3 h 10 min1,140 subs	13 h4,557 subs	51 h18,225 subs
Bortle 9Inner city	5 h 50 min2,103 subs	23 h8,410 subs	93 h33,639 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 5 h 44 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 Pinwheel Galaxy is 29′ × 27′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 33% 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	1 h 35 min569 subs	2 h 42 min975 subs	7 h 38 min2,750 subs
20 s	1 h 20 min239 subs	2 h 27 min442 subs	7 h 23 min1,329 subs
30 s	1 h 15 min150 subs	2 h 22 min285 subs	7 h 18 min876 subs

About the Pinwheel Galaxy

Big, face-on and faint. Its total magnitude is flattering; spread over half a degree the arms are dim and demand hours, especially from suburban skies.

M101, NGC 5457 · Galaxy in Ursa Major · magnitude 7.9 · 29′ × 27′ · best in Apr, May, Jun. 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 Pinwheel 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 Pinwheel 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 Pinwheel Galaxy · All targets for the Vespera 3