How long to image the Orion Nebula with the Unistellar eQuinox 2

From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 15 min (224 subs of 4 s) for a solid image of the Orion Nebula. A quick look takes 4 min; a showpiece 1 h. 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 is 2.5× wider than the frame.

Orion Nebula with the Unistellar eQuinox 2: 4 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site2 min33 subs9 min129 subs34 min514 subs
Bortle 2Typical dark site2 min33 subs9 min132 subs35 min526 subs
Bortle 3Rural2 min35 subs9 min137 subs36 min548 subs
Bortle 4Rural / suburban transition3 min38 subs10 min151 subs40 min601 subs
Bortle 5Suburban3 min43 subs11 min172 subs46 min686 subs
Bortle 6Bright suburban4 min56 subs15 min224 subs1 h894 subs
Bortle 7Suburban / urban transition5 min81 subs21 min323 subs1 h 26 min1,290 subs
Bortle 8City8 min120 subs32 min477 subs2 h 07 min1,906 subs
Bortle 9Inner city13 min202 subs54 min805 subs3 h 35 min3,218 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 19 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, and 30% off the battery for a December night.)

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How it frames

The Orion Nebula is 85′ × 60′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it is 2.5× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.

Filters

The Orion Nebula is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the eQuinox 2 has no dual-band option: 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 figures above are for the No filter position, and a darker sky is the lever that remains.

About the Orion Nebula

The brightest nebula in the northern sky and the one every smart scope gets pointed at first. The core saturates in a minute; the wings and the Running Man need real time. Mix short and long stacks.

M42, NGC 1976 · Emission nebula in Orion · magnitude 4.0 · 85′ × 60′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.

Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.

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

Have an image of the Orion Nebula 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 Orion Nebula · All targets for the eQuinox 2