How long to image the M10 with the Vaonis Vespera II

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 27 min (165 subs of 10 s) for a solid image of the M10. A quick look takes 7 min; a showpiece 1 h 50 min. Under a Bortle 3 rural sky the solid figure drops to 12 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 23% of the frame’s short side.

M10 with the Vaonis Vespera II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site3 min16 subs10 min62 subs41 min248 subs
Bortle 2Typical dark site3 min17 subs11 min65 subs43 min260 subs
Bortle 3Rural3 min18 subs12 min71 subs47 min284 subs
Bortle 4Rural / suburban transition4 min22 subs14 min86 subs57 min342 subs
Bortle 5Suburban5 min28 subs18 min109 subs1 h 12 min434 subs
Bortle 6Bright suburban7 min42 subs27 min165 subs1 h 50 min659 subs
Bortle 7Suburban / urban transition11 min68 subs45 min272 subs3 h 01 min1,088 subs
Bortle 8City18 min110 subs1 h 13 min439 subs4 h 52 min1,754 subs
Bortle 9Inner city33 min199 subs2 h 12 min794 subs8 h 49 min3,174 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 36 min of run time. The Vespera II’s battery (rated about 4 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 M10 is 20′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 23% 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 s12 min71 subs18 min109 subs45 min272 subs
20 s10 min32 subs17 min50 subs44 min132 subs
30 s15 min30 subs16 min33 subs43 min87 subs

About the M10

A bright globular in Ophiuchus, three degrees from its twin M12. Both fit a short session.

NGC 6254 · Globular cluster in Ophiuchus · magnitude 6.6 · 20′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.

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.

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Imaged the M10 with your Vespera II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M10 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 M10 · All targets for the Vespera II