How long to image the Cocoon Nebula with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 4 h 25 min (3,978 subs of 4 s) for a solid image of the Cocoon Nebula. A quick look takes 1 h 06 min; a showpiece 18 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 31 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 35% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 35 min524 subs | 2 h 20 min2,096 subs | 9 h 19 min8,383 subs |
| Bortle 2Typical dark site | 36 min539 subs | 2 h 24 min2,154 subs | 9 h 34 min8,614 subs |
| Bortle 3Rural | 38 min566 subs | 2 h 31 min2,263 subs | 10 h9,051 subs |
| Bortle 4Rural / suburban transition | 42 min632 subs | 2 h 49 min2,528 subs | 11 h10,111 subs |
| Bortle 5Suburban | 49 min737 subs | 3 h 17 min2,948 subs | 13 h11,791 subs |
| Bortle 6Bright suburban | 1 h 06 min995 subs | 4 h 25 min3,978 subs | 18 h15,912 subs |
| Bortle 7Suburban / urban transition | 1 h 39 min1,486 subs | 6 h 36 min5,941 subs | 26 h23,764 subs |
| Bortle 8City | 2 h 30 min2,248 subs | 9 h 59 min8,989 subs | 40 h35,955 subs |
| Bortle 9Inner city | 4 h 18 min3,873 subs | 17 h15,489 subs | 69 h61,956 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 5 h 45 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.
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Everything that fits the eQuinox 2 →
How it frames
The Cocoon Nebula is 12′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 35% of the frame’s short side.
Filters
The Cocoon 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 Cocoon Nebula
A round emission and reflection nebula at the end of a long dark lane. Mixed light, so a broadband stack keeps the blue.
IC 5146, Caldwell 19 · Emission nebula in Cygnus · magnitude 7.2 · 12′ · 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 Cocoon 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
- Cocoon Nebula with the ZWO Seestar S50: 2 h 58 min from Bortle 6
- Cocoon Nebula with the ZWO Seestar S50 Pro: 3 h 20 min from Bortle 6
- Cocoon Nebula with the ZWO Seestar S30: 3 h 29 min from Bortle 6
- Cocoon Nebula with the ZWO Seestar S30 Pro: 3 h 36 min from Bortle 6
- Cocoon Nebula with the DwarfLab DWARF 3: 3 h 39 min from Bortle 6
- Cocoon Nebula with the DwarfLab DWARF mini: 2 h 55 min from Bortle 6
- Cocoon Nebula with the DwarfLab Draco: 2 h 21 min from Bortle 6
- Cocoon Nebula with the DwarfLab DWARF II: 17 h from Bortle 6
- Cocoon Nebula with the Vaonis Vespera II: 4 h 49 min from Bortle 6
- Cocoon Nebula with the Vaonis Vespera Pro: 11 h from Bortle 6
- Cocoon Nebula with the Vaonis Vespera 3: 4 h 36 min from Bortle 6
- Cocoon Nebula with the Vaonis Vespera Pro 2: 10 h from Bortle 6
- Cocoon Nebula with the Unistellar Odyssey: 21 h from Bortle 6
- Cocoon Nebula with the Celestron Origin: 1 h 16 min from Bortle 6
- Cocoon Nebula with the Celestron Origin Mark II: 1 h 44 min from Bortle 6
All telescopes for the Cocoon Nebula · All targets for the eQuinox 2