How long to image the NGC 2403 with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 2 h 57 min (2,657 subs of 4 s) for a solid image of the NGC 2403. A quick look takes 44 min; a showpiece 12 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 41 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 61% 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 | 23 min352 subs | 1 h 34 min1,405 subs | 6 h 14 min5,617 subs |
| Bortle 2Typical dark site | 24 min361 subs | 1 h 36 min1,443 subs | 6 h 25 min5,771 subs |
| Bortle 3Rural | 25 min379 subs | 1 h 41 min1,516 subs | 6 h 44 min6,062 subs |
| Bortle 4Rural / suburban transition | 28 min423 subs | 1 h 53 min1,692 subs | 7 h 31 min6,767 subs |
| Bortle 5Suburban | 33 min493 subs | 2 h 11 min1,971 subs | 8 h 46 min7,884 subs |
| Bortle 6Bright suburban | 44 min665 subs | 2 h 57 min2,657 subs | 12 h10,626 subs |
| Bortle 7Suburban / urban transition | 1 h 06 min991 subs | 4 h 24 min3,963 subs | 18 h15,851 subs |
| Bortle 8City | 1 h 40 min1,498 subs | 6 h 39 min5,991 subs | 27 h23,964 subs |
| Bortle 9Inner city | 2 h 52 min2,580 subs | 11 h10,317 subs | 46 h41,265 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 50 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 NGC 2403 is 21′ × 12′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 61% of the frame’s short side.
About the NGC 2403
A big, loose spiral in Camelopardalis that looks like a small M33, with bright H II regions dual-band can pick out.
Caldwell 7 · Galaxy in Camelopardalis · magnitude 8.9 · 21′ × 12′ · best in Dec, Jan, Feb. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.
Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.
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 NGC 2403 from a eQuinox 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- NGC 2403 with the ZWO Seestar S50: 3 h 13 min from Bortle 6
- NGC 2403 with the ZWO Seestar S50 Pro: 3 h 32 min from Bortle 6
- NGC 2403 with the ZWO Seestar S30: 3 h 23 min from Bortle 6
- NGC 2403 with the ZWO Seestar S30 Pro: 3 h 44 min from Bortle 6
- NGC 2403 with the DwarfLab DWARF 3: 4 h 40 min from Bortle 6
- NGC 2403 with the DwarfLab DWARF mini: 3 h 13 min from Bortle 6
- NGC 2403 with the DwarfLab Draco: 2 h 39 min from Bortle 6
- NGC 2403 with the DwarfLab DWARF II: 11 h from Bortle 6
- NGC 2403 with the Vaonis Vespera II: 3 h 13 min from Bortle 6
- NGC 2403 with the Vaonis Vespera Pro: 7 h 14 min from Bortle 6
- NGC 2403 with the Vaonis Vespera 3: 3 h 05 min from Bortle 6
- NGC 2403 with the Vaonis Vespera Pro 2: 6 h 53 min from Bortle 6
- NGC 2403 with the Unistellar Odyssey: 14 h from Bortle 6
- NGC 2403 with the Celestron Origin: 51 min from Bortle 6
- NGC 2403 with the Celestron Origin Mark II: 1 h 10 min from Bortle 6
All telescopes for the NGC 2403 · All targets for the eQuinox 2