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

About 52 min of total integration for a solid image, or 3 h 29 min for a showpiece. A quick look takes 13 min.

How many subs is that on the Vespera Pro?

At the default 10 s sub length, 314 subs for a solid image from Bortle 6 and 161 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 Pro

From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 52 min (314 subs of 10 s) for a solid image of the Spindle Galaxy. A quick look takes 13 min; a showpiece 3 h 29 min. Under a Bortle 3 rural sky the solid figure drops to 27 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 Pro: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	6 min37 subs	24 min146 subs	1 h 37 min583 subs
Bortle 2Typical dark site	6 min38 subs	25 min151 subs	1 h 41 min604 subs
Bortle 3Rural	7 min41 subs	27 min161 subs	1 h 47 min643 subs
Bortle 4Rural / suburban transition	8 min47 subs	31 min185 subs	2 h 03 min737 subs
Bortle 5Suburban	9 min56 subs	37 min222 subs	2 h 28 min887 subs
Bortle 6Bright suburban	13 min79 subs	52 min314 subs	3 h 29 min1,254 subs
Bortle 7Suburban / urban transition	20 min123 subs	1 h 21 min489 subs	5 h 26 min1,954 subs
Bortle 8City	32 min190 subs	2 h 07 min760 subs	8 h 27 min3,040 subs
Bortle 9Inner city	56 min335 subs	3 h 43 min1,340 subs	15 h5,357 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 08 min of run time. The Vespera Pro’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 30WExtends the 11 h battery; 30 W PD per Vaonis.
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How it frames

The Spindle Galaxy is 4.7′ × 1.9′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ 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, no EQ mode. Time for a solid image by sub length:

Sub length	Bortle 3	Bortle 5	Bortle 7
10 s	27 min161 subs	37 min222 subs	1 h 21 min489 subs
20 s	24 min71 subs	34 min102 subs	1 h 18 min235 subs
30 s	22 min45 subs	33 min66 subs	1 h 17 min155 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 Pro

The square-sensor Vespera with 2 µm pixels. Higher resolution than the II, and correspondingly slower per pixel: expect around double the time for the same per-pixel SNR. Run-out in 2026 and replaced by the Vespera Pro 2.

10 s subs by default; Expert Mode manual targets allow 1 to 30 s. Alt-azimuth only, no EQ mode. Optional clip-on Vaonis filters: dual-band, light-pollution (CLS) and solar.

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.

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Imaged the Spindle Galaxy with your Vespera Pro? 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 Pro? 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 Pro