How long should I image the Sagittarius Star Cloud with the Vespera 3 from a Bortle 6 sky?

About 8 min of total integration for a solid image, or 34 min for a showpiece. A quick look takes 2 min.

How many subs is that on the Vespera 3?

At the default 10 s sub length, 51 subs for a solid image from Bortle 6 and 30 from Bortle 3.

Does a dual-band filter help on the Sagittarius Star Cloud?

No. The Sagittarius Star Cloud is a broadband target and a dual-band filter blocks most of its light. Shoot without a filter.

How long to image the Sagittarius Star Cloud with the Vaonis Vespera 3

From a Bortle 6 suburban sky, the Vaonis Vespera 3 needs about 8 min (51 subs of 10 s) for a solid image of the Sagittarius Star Cloud. A quick look takes 2 min; a showpiece 34 min. Under a Bortle 3 rural sky the solid figure drops to 5 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 is just over the frame at 1.0×.

Sagittarius Star Cloud 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 min10 subs	5 min30 subs	15 min91 subs
Bortle 2Typical dark site	2 min10 subs	5 min30 subs	16 min94 subs
Bortle 3Rural	2 min10 subs	5 min30 subs	17 min101 subs
Bortle 4Rural / suburban transition	2 min10 subs	5 min30 subs	19 min117 subs
Bortle 5Suburban	2 min10 subs	6 min36 subs	24 min142 subs
Bortle 6Bright suburban	2 min13 subs	8 min51 subs	34 min203 subs
Bortle 7Suburban / urban transition	3 min20 subs	13 min80 subs	53 min320 subs
Bortle 8City	5 min32 subs	21 min126 subs	1 h 24 min502 subs
Bortle 9Inner city	9 min56 subs	37 min223 subs	2 h 28 min889 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 11 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 Sagittarius Star Cloud is 90′ across. The Vespera 3 frames 2.60° × 1.46° at 2.44″ per pixel, so it is just over the frame at 1.0×. Point at the part you want; the edges will fall outside the frame.

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	5 min30 subs	6 min36 subs	13 min80 subs
20 s	10 min30 subs	10 min30 subs	13 min39 subs
30 s	15 min30 subs	15 min30 subs	15 min30 subs

About the Sagittarius Star Cloud

A window through the dust into the inner Milky Way, densely packed with stars. Short stacks are enough; it is stars, not nebulosity.

M24, IC 4715 · Star cloud in Sagittarius · magnitude 4.6 · 90′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Star clouds are dense fields of ordinary stars rather than nebulosity. Short subs, no filter, and a modest total keep the field from saturating while still showing the depth of the Milky Way.

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

Have an image of the Sagittarius Star Cloud 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 Sagittarius Star Cloud · All targets for the Vespera 3