How long to image the M59 with the Vaonis Vespera Pro

From a Bortle 6 suburban sky, the Vaonis Vespera Pro needs about 1 h 47 min (643 subs of 10 s) for a solid image of the M59. A quick look takes 27 min; a showpiece 7 h 08 min. Under a Bortle 3 rural sky the solid figure drops to 51 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.

M59 with the Vaonis Vespera Pro: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site11 min68 subs45 min272 subs3 h 01 min1,087 subs
Bortle 2Typical dark site12 min71 subs47 min283 subs3 h 09 min1,132 subs
Bortle 3Rural13 min77 subs51 min305 subs3 h 23 min1,218 subs
Bortle 4Rural / suburban transition15 min90 subs59 min357 subs3 h 58 min1,427 subs
Bortle 5Suburban18 min110 subs1 h 13 min440 subs4 h 53 min1,758 subs
Bortle 6Bright suburban27 min161 subs1 h 47 min643 subs7 h 08 min2,569 subs
Bortle 7Suburban / urban transition43 min258 subs2 h 51 min1,029 subs11 h4,115 subs
Bortle 8City1 h 08 min408 subs4 h 31 min1,629 subs18 h6,516 subs
Bortle 9Inner city2 h 01 min728 subs8 h 05 min2,909 subs32 h11,636 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 2 h 19 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 M59 is 5′ × 3.5′ across. The Vespera Pro frames 1.62° × 1.62° at 1.65″ 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 lengthBortle 3Bortle 5Bortle 7
10 s51 min305 subs1 h 13 min440 subs2 h 51 min1,029 subs
20 s44 min131 subs1 h 06 min199 subs2 h 44 min494 subs
30 s41 min83 subs1 h 04 min128 subs2 h 42 min325 subs

About the M59

An elliptical galaxy in Virgo, close to M60. A smudge, but a bright one.

NGC 4621 · Galaxy in Virgo · magnitude 9.6 · 5′ × 3.5′ · 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 M59 with your Vespera Pro? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M59 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 M59 · All targets for the Vespera Pro