How long to image the Triangulum Galaxy with the Vaonis Vespera II

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 2 h 42 min (971 subs of 10 s) for a solid image of the Triangulum Galaxy. A quick look takes 40 min; a showpiece 11 h. Under a Bortle 3 rural sky the solid figure drops to 1 h. 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 85% of the frame’s short side.

Triangulum Galaxy with the Vaonis Vespera II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site13 min76 subs50 min303 subs3 h 22 min1,210 subs
Bortle 2Typical dark site13 min81 subs54 min323 subs3 h 35 min1,292 subs
Bortle 3Rural15 min91 subs1 h362 subs4 h 01 min1,447 subs
Bortle 4Rural / suburban transition19 min114 subs1 h 16 min456 subs5 h 04 min1,824 subs
Bortle 5Suburban25 min152 subs1 h 41 min605 subs6 h 43 min2,420 subs
Bortle 6Bright suburban40 min243 subs2 h 42 min971 subs11 h3,884 subs
Bortle 7Suburban / urban transition1 h 10 min418 subs4 h 38 min1,669 subs19 h6,673 subs
Bortle 8City1 h 55 min688 subs7 h 38 min2,751 subs31 h11,004 subs
Bortle 9Inner city3 h 31 min1,265 subs14 h5,060 subs56 h20,239 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 30 min of run time. The Vespera II’s battery is rated at about 4 h, which is cutting it fine; take a power bank. (Bortle 6, solid image; we allow 30% over the integration time.)

Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.

Everything that fits the Vespera II →

How it frames

The Triangulum Galaxy is 73′ × 45′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 85% 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 lengthBortle 3Bortle 5Bortle 7
10 s1 h362 subs1 h 41 min605 subs4 h 38 min1,669 subs
20 s51 min153 subs1 h 31 min274 subs4 h 29 min806 subs
30 s48 min96 subs1 h 28 min177 subs4 h 25 min531 subs

About the Triangulum Galaxy

Big, face-on and low in surface brightness. Nearly as bright as M31 overall but spread thin, so it needs far more time. Its H II regions pop with a dual-band filter.

M33, NGC 598 · Galaxy in Triangulum · magnitude 5.7 · 73′ × 45′ · best in Sep, Oct, Nov. 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 DirectAmazon UKAmazon 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 Triangulum 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 Triangulum 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 Triangulum Galaxy · All targets for the Vespera II