How long to image the Elephant's Trunk Nebula with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 3 h 32 min (3,183 subs of 4 s) for a solid image of the Elephant's Trunk Nebula. A quick look takes 53 min; a showpiece 14 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 01 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is 5.0× wider than the frame.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 28 min420 subs | 1 h 52 min1,677 subs | 7 h 27 min6,706 subs |
| Bortle 2Typical dark site | 29 min431 subs | 1 h 55 min1,723 subs | 7 h 39 min6,891 subs |
| Bortle 3Rural | 30 min453 subs | 2 h 01 min1,811 subs | 8 h 03 min7,241 subs |
| Bortle 4Rural / suburban transition | 34 min506 subs | 2 h 15 min2,023 subs | 8 h 59 min8,089 subs |
| Bortle 5Suburban | 39 min590 subs | 2 h 37 min2,359 subs | 10 h9,433 subs |
| Bortle 6Bright suburban | 53 min796 subs | 3 h 32 min3,183 subs | 14 h12,729 subs |
| Bortle 7Suburban / urban transition | 1 h 19 min1,189 subs | 5 h 17 min4,753 subs | 21 h19,011 subs |
| Bortle 8City | 2 h1,798 subs | 7 h 59 min7,191 subs | 32 h28,764 subs |
| Bortle 9Inner city | 3 h 27 min3,098 subs | 14 h12,392 subs | 55 h49,565 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 4 h 36 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.)
- 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.
Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.
Everything that fits the eQuinox 2 →
How it frames
The Elephant's Trunk Nebula is 170′ × 140′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it is 5.0× 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 Elephant's Trunk 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 Elephant's Trunk Nebula
A vast, faint hydrogen cloud in Cepheus with the dark trunk winding through it. Huge, so wide scopes frame the whole thing; dual-band is essential from any lit sky.
IC 1396 · Emission nebula in Cepheus · magnitude 3.5 · 170′ × 140′ · best in Jul, Aug, Sep. 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.
Have an image of the Elephant's Trunk 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
- Elephant's Trunk Nebula with the ZWO Seestar S50: 2 h 22 min from Bortle 6
- Elephant's Trunk Nebula with the ZWO Seestar S50 Pro: 2 h 40 min from Bortle 6
- Elephant's Trunk Nebula with the ZWO Seestar S30: 2 h 47 min from Bortle 6
- Elephant's Trunk Nebula with the ZWO Seestar S30 Pro: 2 h 53 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab DWARF 3: 2 h 55 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab DWARF mini: 2 h 20 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab Draco: 1 h 52 min from Bortle 6
- Elephant's Trunk Nebula with the DwarfLab DWARF II: 13 h from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera II: 3 h 51 min from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera Pro: 8 h 39 min from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera 3: 3 h 41 min from Bortle 6
- Elephant's Trunk Nebula with the Vaonis Vespera Pro 2: 8 h 15 min from Bortle 6
- Elephant's Trunk Nebula with the Unistellar Odyssey: 16 h from Bortle 6
- Elephant's Trunk Nebula with the Celestron Origin: 1 h 01 min from Bortle 6
- Elephant's Trunk Nebula with the Celestron Origin Mark II: 1 h 24 min from Bortle 6
All telescopes for the Elephant's Trunk Nebula · All targets for the eQuinox 2