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

About 24 min of total integration for a solid image, or 1 h 34 min for a showpiece. A quick look takes 6 min.

How many subs is that on the Vespera II?

At the default 10 s sub length, 142 subs for a solid image from Bortle 6 and 69 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 II

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 24 min (142 subs of 10 s) for a solid image of the Spindle Galaxy. A quick look takes 6 min; a showpiece 1 h 34 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 II: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	3 min16 subs	10 min62 subs	41 min247 subs
Bortle 2Typical dark site	3 min17 subs	11 min65 subs	43 min257 subs
Bortle 3Rural	3 min18 subs	11 min69 subs	46 min275 subs
Bortle 4Rural / suburban transition	3 min20 subs	13 min80 subs	53 min320 subs
Bortle 5Suburban	4 min25 subs	16 min98 subs	1 h 05 min391 subs
Bortle 6Bright suburban	6 min36 subs	24 min142 subs	1 h 34 min566 subs
Bortle 7Suburban / urban transition	9 min57 subs	37 min225 subs	2 h 30 min899 subs
Bortle 8City	15 min89 subs	59 min354 subs	3 h 56 min1,415 subs
Bortle 9Inner city	26 min158 subs	1 h 45 min630 subs	6 h 59 min2,517 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 31 min of run time. The Vespera II’s battery (rated about 4 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 30WOnly four hours inside; Vaonis specifies a 30 W PD source. C-to-C cable not included.
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Vaonis Vespera hygrometer sensorTriggers the built-in demister automatically; the correct dew accessory for the II.
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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 II frames 2.55° × 1.44° at 2.39″ 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	11 min69 subs	16 min98 subs	37 min225 subs
20 s	10 min31 subs	15 min46 subs	36 min109 subs
30 s	15 min30 subs	15 min30 subs	36 min72 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 II

A 50 mm quadruplet on an 8 MP sensor with Vaonis’s mosaic mode for wide fields. Same optics class as the Seestar S50, four times the pixels.

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; the app detects which is fitted.

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 IIVaonis 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 II? 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 II? 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 II