How long to image the Iris Nebula with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 1 h 43 min (1,549 subs of 4 s) for a solid image of the Iris Nebula. A quick look takes 26 min; a showpiece 6 h 53 min. Under a Bortle 3 rural sky the solid figure drops to 59 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 53% 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 | 14 min207 subs | 55 min828 subs | 3 h 41 min3,312 subs |
| Bortle 2Typical dark site | 14 min213 subs | 57 min851 subs | 3 h 47 min3,401 subs |
| Bortle 3Rural | 15 min223 subs | 59 min892 subs | 3 h 58 min3,568 subs |
| Bortle 4Rural / suburban transition | 17 min249 subs | 1 h 06 min994 subs | 4 h 25 min3,974 subs |
| Bortle 5Suburban | 19 min289 subs | 1 h 17 min1,155 subs | 5 h 08 min4,617 subs |
| Bortle 6Bright suburban | 26 min388 subs | 1 h 43 min1,549 subs | 6 h 53 min6,195 subs |
| Bortle 7Suburban / urban transition | 38 min576 subs | 2 h 33 min2,301 subs | 10 h9,202 subs |
| Bortle 8City | 58 min867 subs | 3 h 51 min3,468 subs | 15 h13,870 subs |
| Bortle 9Inner city | 1 h 39 min1,490 subs | 6 h 37 min5,957 subs | 26 h23,826 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 14 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 Iris Nebula is 18′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 53% of the frame’s short side.
About the Iris Nebula
A blue reflection nebula wrapped in dark dust. No filter helps, and the surrounding dust needs a dark sky and hours.
NGC 7023, Caldwell 4 · Reflection nebula in Cepheus · magnitude 6.8 · 18′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Reflection nebulae are starlight scattered by dust, so they are broadband and blue. A dual-band filter removes almost all of it; do not use one. These are among the faintest structures a smart scope can attempt and the figures run long. A dark sky matters more here than for any other type, and the Moon must be down.
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 Iris 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
- Iris Nebula with the ZWO Seestar S50: 1 h 53 min from Bortle 6
- Iris Nebula with the ZWO Seestar S50 Pro: 2 h 04 min from Bortle 6
- Iris Nebula with the ZWO Seestar S30: 1 h 59 min from Bortle 6
- Iris Nebula with the ZWO Seestar S30 Pro: 2 h 12 min from Bortle 6
- Iris Nebula with the DwarfLab DWARF 3: 2 h 45 min from Bortle 6
- Iris Nebula with the DwarfLab DWARF mini: 1 h 53 min from Bortle 6
- Iris Nebula with the DwarfLab Draco: 1 h 33 min from Bortle 6
- Iris Nebula with the DwarfLab DWARF II: 6 h 29 min from Bortle 6
- Iris Nebula with the Vaonis Vespera II: 1 h 53 min from Bortle 6
- Iris Nebula with the Vaonis Vespera Pro: 4 h 14 min from Bortle 6
- Iris Nebula with the Vaonis Vespera 3: 1 h 48 min from Bortle 6
- Iris Nebula with the Vaonis Vespera Pro 2: 4 h 02 min from Bortle 6
- Iris Nebula with the Unistellar Odyssey: 7 h 58 min from Bortle 6
- Iris Nebula with the Celestron Origin: 30 min from Bortle 6
- Iris Nebula with the Celestron Origin Mark II: 41 min from Bortle 6
All telescopes for the Iris Nebula · All targets for the eQuinox 2