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

About 23 min of total integration for a solid image, or 1 h 30 min for a showpiece. A quick look takes 6 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 136 subs for a solid image from Bortle 6 and 66 from Bortle 3.

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

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

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

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 23 min (136 subs of 10 s) for a solid image of the Spindle Galaxy. A quick look takes 6 min; a showpiece 1 h 30 min. Under a Bortle 3 rural sky the solid figure drops to 11 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 5% of the frame’s short side.

Spindle 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	2 min15 subs	10 min59 subs	39 min235 subs
Bortle 2Typical dark site	3 min16 subs	10 min61 subs	41 min244 subs
Bortle 3Rural	3 min17 subs	11 min66 subs	44 min262 subs
Bortle 4Rural / suburban transition	3 min20 subs	13 min77 subs	51 min305 subs
Bortle 5Suburban	4 min24 subs	16 min94 subs	1 h 02 min373 subs
Bortle 6Bright suburban	6 min34 subs	23 min136 subs	1 h 30 min541 subs
Bortle 7Suburban / urban transition	9 min54 subs	36 min216 subs	2 h 23 min861 subs
Bortle 8City	14 min85 subs	57 min340 subs	3 h 46 min1,357 subs
Bortle 9Inner city	25 min151 subs	1 h 41 min604 subs	6 h 42 min2,415 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 29 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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red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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How it frames

The Spindle Galaxy is 4.7′ × 1.9′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it fills 5% 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	11 min66 subs	16 min94 subs	36 min216 subs
20 s	10 min30 subs	14 min44 subs	35 min105 subs
30 s	15 min30 subs	15 min30 subs	34 min69 subs

About the Spindle Galaxy

An edge-on lenticular with a thin dust lane. Small, but its surface brightness is decent.

M102, NGC 5866 · Galaxy in Draco · magnitude 9.9 · 4.7′ × 1.9′ · 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 Spindle 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 Spindle 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 Spindle Galaxy · All targets for the Vespera 3