How long to image the NGC 2903 with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 2 h 08 min (1,928 subs of 4 s) for a solid image of the NGC 2903. A quick look takes 32 min; a showpiece 8 h 34 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 14 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 37% 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 | 17 min258 subs | 1 h 09 min1,030 subs | 4 h 35 min4,118 subs |
| Bortle 2Typical dark site | 18 min265 subs | 1 h 10 min1,057 subs | 4 h 42 min4,228 subs |
| Bortle 3Rural | 18 min278 subs | 1 h 14 min1,110 subs | 4 h 56 min4,437 subs |
| Bortle 4Rural / suburban transition | 21 min309 subs | 1 h 22 min1,236 subs | 5 h 29 min4,943 subs |
| Bortle 5Suburban | 24 min359 subs | 1 h 36 min1,436 subs | 6 h 23 min5,744 subs |
| Bortle 6Bright suburban | 32 min482 subs | 2 h 08 min1,928 subs | 8 h 34 min7,710 subs |
| Bortle 7Suburban / urban transition | 48 min717 subs | 3 h 11 min2,865 subs | 13 h11,457 subs |
| Bortle 8City | 1 h 12 min1,080 subs | 4 h 48 min4,319 subs | 19 h17,274 subs |
| Bortle 9Inner city | 2 h 04 min1,855 subs | 8 h 15 min7,420 subs | 33 h29,680 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 2 h 47 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 February 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 2903 is 12.6′ × 6′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 37% of the frame’s short side.
About the NGC 2903
A bright barred spiral below the Sickle of Leo that Messier somehow missed. Bright core, well-defined arms.
UGC 5079 · Galaxy in Leo · magnitude 9.0 · 12.6′ × 6′ · best in Jan, Feb, Mar. 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 2903 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 2903 with the ZWO Seestar S50: 2 h 21 min from Bortle 6
- NGC 2903 with the ZWO Seestar S50 Pro: 2 h 34 min from Bortle 6
- NGC 2903 with the ZWO Seestar S30: 2 h 28 min from Bortle 6
- NGC 2903 with the ZWO Seestar S30 Pro: 2 h 44 min from Bortle 6
- NGC 2903 with the DwarfLab DWARF 3: 3 h 25 min from Bortle 6
- NGC 2903 with the DwarfLab DWARF mini: 2 h 20 min from Bortle 6
- NGC 2903 with the DwarfLab Draco: 1 h 56 min from Bortle 6
- NGC 2903 with the DwarfLab DWARF II: 8 h 04 min from Bortle 6
- NGC 2903 with the Vaonis Vespera II: 2 h 21 min from Bortle 6
- NGC 2903 with the Vaonis Vespera Pro: 5 h 16 min from Bortle 6
- NGC 2903 with the Vaonis Vespera 3: 2 h 15 min from Bortle 6
- NGC 2903 with the Vaonis Vespera Pro 2: 5 h 01 min from Bortle 6
- NGC 2903 with the Unistellar Odyssey: 9 h 55 min from Bortle 6
- NGC 2903 with the Celestron Origin: 37 min from Bortle 6
- NGC 2903 with the Celestron Origin Mark II: 51 min from Bortle 6
All telescopes for the NGC 2903 · All targets for the eQuinox 2