How long to image the Eskimo Nebula with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 10 min (156 subs of 4 s) for a solid image of the Eskimo Nebula. A quick look takes 3 min; a showpiece 41 min. Under a Bortle 3 rural sky the solid figure drops to 7 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is small in the frame, about 36 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 2 min25 subs | 6 min97 subs | 26 min386 subs |
| Bortle 2Typical dark site | 2 min25 subs | 7 min99 subs | 26 min394 subs |
| Bortle 3Rural | 2 min26 subs | 7 min102 subs | 27 min407 subs |
| Bortle 4Rural / suburban transition | 2 min28 subs | 7 min110 subs | 29 min440 subs |
| Bortle 5Suburban | 2 min31 subs | 8 min124 subs | 33 min493 subs |
| Bortle 6Bright suburban | 3 min39 subs | 10 min156 subs | 41 min622 subs |
| Bortle 7Suburban / urban transition | 4 min55 subs | 14 min217 subs | 58 min867 subs |
| Bortle 8City | 5 min79 subs | 21 min313 subs | 1 h 23 min1,249 subs |
| Bortle 9Inner city | 9 min129 subs | 34 min516 subs | 2 h 17 min2,062 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 13 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 January night.)
- USB-C power bank 20000mAh 5V 2AUnistellar asks for a 5 V 2 A output; PD is not needed.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
- hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
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Everything that fits the eQuinox 2 →
How it frames
The Eskimo Nebula is 0.8′ × 0.7′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it is small in the frame, about 36 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.
Filters
The Eskimo 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 Eskimo Nebula
A small, bright double-shell planetary in Gemini. Tiny in a smart scope but intense; a few minutes show the disc.
NGC 2392, Caldwell 39, Clown Face · Planetary nebula in Gemini · magnitude 9.2 · 0.8′ × 0.7′ · best in Dec, Jan, Feb. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.
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.
Have an image of the Eskimo 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
- Eskimo Nebula with the ZWO Seestar S50: 10 min from Bortle 6
- Eskimo Nebula with the ZWO Seestar S50 Pro: 11 min from Bortle 6
- Eskimo Nebula with the ZWO Seestar S30: 11 min from Bortle 6
- Eskimo Nebula with the ZWO Seestar S30 Pro: 12 min from Bortle 6
- Eskimo Nebula with the DwarfLab DWARF 3: 14 min from Bortle 6
- Eskimo Nebula with the DwarfLab DWARF mini: 10 min from Bortle 6
- Eskimo Nebula with the DwarfLab Draco: 15 min from Bortle 6
- Eskimo Nebula with the DwarfLab DWARF II: 40 min from Bortle 6
- Eskimo Nebula with the Vaonis Vespera II: 12 min from Bortle 6
- Eskimo Nebula with the Vaonis Vespera Pro: 27 min from Bortle 6
- Eskimo Nebula with the Vaonis Vespera 3: 12 min from Bortle 6
- Eskimo Nebula with the Vaonis Vespera Pro 2: 26 min from Bortle 6
- Eskimo Nebula with the Unistellar Odyssey: 46 min from Bortle 6
- Eskimo Nebula with the Celestron Origin: 5 min from Bortle 6
- Eskimo Nebula with the Celestron Origin Mark II: 5 min from Bortle 6
All telescopes for the Eskimo Nebula · All targets for the eQuinox 2