How long to image the M14 with the Vaonis Vespera II

From a Bortle 6 suburban sky, the Vaonis Vespera II needs about 23 min (136 subs of 10 s) for a solid image of the M14. A quick look takes 6 min; a showpiece 1 h 31 min. Under a Bortle 3 rural sky the solid figure drops to 10 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 13% of the frame’s short side.

M14 with the Vaonis Vespera II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site2 min14 subs9 min55 subs37 min220 subs
Bortle 2Typical dark site2 min15 subs10 min58 subs38 min230 subs
Bortle 3Rural3 min16 subs10 min63 subs41 min249 subs
Bortle 4Rural / suburban transition3 min19 subs12 min74 subs49 min294 subs
Bortle 5Suburban4 min23 subs15 min92 subs1 h 01 min367 subs
Bortle 6Bright suburban6 min34 subs23 min136 subs1 h 31 min544 subs
Bortle 7Suburban / urban transition9 min56 subs37 min221 subs2 h 27 min881 subs
Bortle 8City15 min88 subs59 min352 subs3 h 54 min1,406 subs
Bortle 9Inner city26 min158 subs1 h 45 min631 subs7 h 01 min2,524 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 29 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 M14 is 11′ across. The Vespera II frames 2.55° × 1.44° at 2.39″ per pixel, so it fills 13% 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 s10 min63 subs15 min92 subs37 min221 subs
20 s10 min30 subs14 min43 subs36 min107 subs
30 s15 min30 subs15 min30 subs35 min71 subs

About the M14

A fainter, more distant globular in Ophiuchus. Takes longer than its neighbours to resolve.

NGC 6402 · Globular cluster in Ophiuchus · magnitude 7.6 · 11′ · 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 M14 with your Vespera II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M14 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 M14 · All targets for the Vespera II