How long to image the M70 with the Unistellar eQuinox 2

From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 14 min (211 subs of 4 s) for a solid image of the M70. A quick look takes 4 min; a showpiece 56 min. Under a Bortle 3 rural sky the solid figure drops to 9 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 23% of the frame’s short side.

M70 with the Unistellar eQuinox 2: 4 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site2 min32 subs8 min127 subs34 min505 subs
Bortle 2Typical dark site2 min33 subs9 min129 subs34 min515 subs
Bortle 3Rural2 min34 subs9 min134 subs36 min535 subs
Bortle 4Rural / suburban transition2 min37 subs10 min146 subs39 min582 subs
Bortle 5Suburban3 min42 subs11 min165 subs44 min657 subs
Bortle 6Bright suburban4 min53 subs14 min211 subs56 min842 subs
Bortle 7Suburban / urban transition5 min75 subs20 min299 subs1 h 20 min1,194 subs
Bortle 8City7 min109 subs29 min435 subs1 h 56 min1,740 subs
Bortle 9Inner city12 min182 subs48 min726 subs3 h 14 min2,904 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 18 min of run time. The eQuinox 2’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 M70 is 8′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 23% of the frame’s short side.

About the M70

M69's near twin two degrees east, a compact globular in the same low field.

NGC 6681 · Globular cluster in Sagittarius · magnitude 7.9 · 8′ · best in Jun, Jul, Aug. 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 Unistellar eQuinox 2

A 114 mm Newtonian with five times the light grasp of a 50 mm refractor. Fixed 4 s subs put it in read-noise territory under dark skies, but the aperture carries it. The published field is 45.6′ × 34.2′, a crop of the sensor.

Fixed 4 s subs in Enhanced Vision; they cannot be changed. No built-in filter. Unistellar sells only a solar filter and says a third-party filter is at your own risk and voids the warranty.

The eQuinox 2 uses fixed 4 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.

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 M70 with your eQuinox 2? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M70 from a eQuinox 2? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the M70 · All targets for the eQuinox 2