How long to image the M87 with the Vaonis Vespera Pro

From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 2 h 20 min (839 subs of 10 s) for a solid image of the M87. A quick look takes 35 min; a showpiece 9 h 19 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 04 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 8% of the frame’s short side.

M87 with the Vaonis Vespera Pro: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site14 min85 subs56 min338 subs3 h 45 min1,349 subs
Bortle 2Typical dark site15 min89 subs59 min353 subs3 h 55 min1,411 subs
Bortle 3Rural16 min96 subs1 h 04 min382 subs4 h 14 min1,527 subs
Bortle 4Rural / suburban transition19 min114 subs1 h 15 min453 subs5 h 01 min1,809 subs
Bortle 5Suburban24 min142 subs1 h 34 min565 subs6 h 16 min2,257 subs
Bortle 6Bright suburban35 min210 subs2 h 20 min839 subs9 h 19 min3,354 subs
Bortle 7Suburban / urban transition57 min341 subs3 h 47 min1,362 subs15 h5,445 subs
Bortle 8City1 h 31 min544 subs6 h 02 min2,173 subs24 h8,692 subs
Bortle 9Inner city2 h 43 min976 subs11 h3,904 subs43 h15,616 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h 02 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 M87 is 8′ × 7′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ per pixel, so it fills 8% 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 h 04 min382 subs1 h 34 min565 subs3 h 47 min1,362 subs
20 s54 min163 subs1 h 24 min254 subs3 h 37 min652 subs
30 s51 min102 subs1 h 21 min163 subs3 h 34 min429 subs

About the M87

The supergiant elliptical at the heart of the Virgo cluster, home of the first-photographed black hole. Bright, round, structureless.

NGC 4486, Virgo A · Galaxy in Virgo · magnitude 8.6 · 8′ × 7′ · best in Mar, Apr, May. 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 M87 with your Vespera Pro? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M87 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 M87 · All targets for the Vespera Pro