How long to image the Southern Pinwheel with the Unistellar eQuinox 2

From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 42 min (628 subs of 4 s) for a solid image of the Southern Pinwheel. A quick look takes 10 min; a showpiece 2 h 47 min. Under a Bortle 3 rural sky the solid figure drops to 25 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 38% of the frame’s short side.

Southern Pinwheel with the Unistellar eQuinox 2: 4 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site6 min87 subs23 min347 subs1 h 32 min1,386 subs
Bortle 2Typical dark site6 min89 subs24 min355 subs1 h 35 min1,420 subs
Bortle 3Rural6 min93 subs25 min372 subs1 h 39 min1,486 subs
Bortle 4Rural / suburban transition7 min103 subs27 min411 subs1 h 50 min1,644 subs
Bortle 5Suburban8 min119 subs32 min474 subs2 h 06 min1,895 subs
Bortle 6Bright suburban10 min157 subs42 min628 subs2 h 47 min2,510 subs
Bortle 7Suburban / urban transition15 min231 subs1 h 01 min921 subs4 h 06 min3,683 subs
Bortle 8City23 min344 subs1 h 32 min1,376 subs6 h 07 min5,504 subs
Bortle 9Inner city39 min587 subs2 h 36 min2,347 subs10 h9,388 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 54 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 Southern Pinwheel is 13′ × 12′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 38% of the frame’s short side.

About the Southern Pinwheel

A bright barred spiral, superb from the southern hemisphere and a low-altitude struggle from northern Europe.

M83, NGC 5236 · Galaxy in Hydra · magnitude 7.6 · 13′ × 12′ · 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 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 Southern Pinwheel with your eQuinox 2? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Southern Pinwheel 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 Southern Pinwheel · All targets for the eQuinox 2