How long to image the M4 with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 1 h 07 min (1,009 subs of 4 s) for a solid image of the M4. A quick look takes 17 min; a showpiece 4 h 29 min. Under a Bortle 3 rural sky the solid figure drops to 39 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is just over the frame at 1.1×.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 9 min137 subs | 36 min546 subs | 2 h 25 min2,182 subs |
| Bortle 2Typical dark site | 9 min140 subs | 37 min560 subs | 2 h 29 min2,239 subs |
| Bortle 3Rural | 10 min147 subs | 39 min587 subs | 2 h 36 min2,346 subs |
| Bortle 4Rural / suburban transition | 11 min163 subs | 43 min652 subs | 2 h 54 min2,607 subs |
| Bortle 5Suburban | 13 min189 subs | 50 min755 subs | 3 h 21 min3,020 subs |
| Bortle 6Bright suburban | 17 min253 subs | 1 h 07 min1,009 subs | 4 h 29 min4,035 subs |
| Bortle 7Suburban / urban transition | 25 min373 subs | 1 h 39 min1,492 subs | 6 h 38 min5,967 subs |
| Bortle 8City | 37 min561 subs | 2 h 29 min2,242 subs | 9 h 58 min8,967 subs |
| Bortle 9Inner city | 1 h 04 min961 subs | 4 h 16 min3,842 subs | 17 h15,365 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 27 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 M4 is 36′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it is just over the frame at 1.1×. Point at the part you want; the edges will fall outside the frame.
About the M4
The loose globular next to Antares. Low in the sky from the UK, so image it near transit.
NGC 6121 · Globular cluster in Scorpius · magnitude 5.9 · 36′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.
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 M4 from a eQuinox 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M4 with the ZWO Seestar S50: 1 h 14 min from Bortle 6
- M4 with the ZWO Seestar S50 Pro: 1 h 21 min from Bortle 6
- M4 with the ZWO Seestar S30: 1 h 18 min from Bortle 6
- M4 with the ZWO Seestar S30 Pro: 1 h 26 min from Bortle 6
- M4 with the DwarfLab DWARF 3: 1 h 48 min from Bortle 6
- M4 with the DwarfLab DWARF mini: 1 h 14 min from Bortle 6
- M4 with the DwarfLab Draco: 1 h 01 min from Bortle 6
- M4 with the DwarfLab DWARF II: 4 h 14 min from Bortle 6
- M4 with the Vaonis Vespera II: 1 h 14 min from Bortle 6
- M4 with the Vaonis Vespera Pro: 2 h 46 min from Bortle 6
- M4 with the Vaonis Vespera 3: 1 h 11 min from Bortle 6
- M4 with the Vaonis Vespera Pro 2: 2 h 39 min from Bortle 6
- M4 with the Unistellar Odyssey: 5 h 11 min from Bortle 6
- M4 with the Celestron Origin: 20 min from Bortle 6
- M4 with the Celestron Origin Mark II: 27 min from Bortle 6