How long to image the Centaurus A with the Vaonis Vespera Pro

From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 1 h 32 min (550 subs of 10 s) for a solid image of the Centaurus A. A quick look takes 23 min; a showpiece 6 h 06 min. Under a Bortle 3 rural sky the solid figure drops to 41 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 27% of the frame’s short side.

Centaurus A with the Vaonis Vespera Pro: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site9 min55 subs36 min217 subs2 h 24 min866 subs
Bortle 2Typical dark site9 min57 subs38 min227 subs2 h 31 min907 subs
Bortle 3Rural10 min62 subs41 min247 subs2 h 44 min985 subs
Bortle 4Rural / suburban transition12 min74 subs49 min293 subs3 h 15 min1,172 subs
Bortle 5Suburban15 min92 subs1 h 01 min368 subs4 h 05 min1,470 subs
Bortle 6Bright suburban23 min138 subs1 h 32 min550 subs6 h 06 min2,199 subs
Bortle 7Suburban / urban transition37 min225 subs2 h 30 min898 subs9 h 58 min3,589 subs
Bortle 8City1 h360 subs3 h 59 min1,437 subs16 h5,747 subs
Bortle 9Inner city1 h 48 min647 subs7 h 11 min2,588 subs29 h10,349 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 59 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.)

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How it frames

The Centaurus A is 26′ × 20′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it fills 27% 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 s41 min247 subs1 h 01 min368 subs2 h 30 min898 subs
20 s35 min104 subs55 min165 subs2 h 23 min430 subs
30 s33 min66 subs53 min106 subs2 h 21 min283 subs

About the Centaurus A

A giant elliptical with a thick dust band across it, the brightest radio galaxy in the sky. A southern-hemisphere showpiece.

NGC 5128, Caldwell 77 · Galaxy in Centaurus · magnitude 6.8 · 26′ × 20′ · best in Mar, Apr, May. Low or below the horizon from northern Europe; best from the southern US southwards.

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 Centaurus A with your Vespera Pro? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Centaurus A 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 Centaurus A · All targets for the Vespera Pro