How long to image the M109 with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 3 h 28 min (3,117 subs of 4 s) for a solid image of the M109. A quick look takes 52 min; a showpiece 14 h. Under a Bortle 3 rural sky the solid figure drops to 2 h. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 22% 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 | 28 min417 subs | 1 h 51 min1,666 subs | 7 h 24 min6,661 subs |
| Bortle 2Typical dark site | 28 min428 subs | 1 h 54 min1,710 subs | 7 h 36 min6,840 subs |
| Bortle 3Rural | 30 min449 subs | 2 h1,795 subs | 7 h 58 min7,177 subs |
| Bortle 4Rural / suburban transition | 33 min500 subs | 2 h 13 min1,999 subs | 8 h 53 min7,994 subs |
| Bortle 5Suburban | 39 min581 subs | 2 h 35 min2,322 subs | 10 h9,288 subs |
| Bortle 6Bright suburban | 52 min780 subs | 3 h 28 min3,117 subs | 14 h12,465 subs |
| Bortle 7Suburban / urban transition | 1 h 17 min1,158 subs | 5 h 09 min4,630 subs | 21 h18,518 subs |
| Bortle 8City | 1 h 56 min1,745 subs | 7 h 45 min6,979 subs | 31 h27,916 subs |
| Bortle 9Inner city | 3 h 20 min2,998 subs | 13 h11,990 subs | 53 h47,959 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 4 h 30 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 M109 is 7.6′ × 4.7′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 22% of the frame’s short side.
About the M109
A barred spiral next to Phecda in the Plough. Faint outer arms, bright bar.
NGC 3992 · Galaxy in Ursa Major · magnitude 9.8 · 7.6′ × 4.7′ · best in Feb, Mar, Apr. 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 M109 from a eQuinox 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M109 with the ZWO Seestar S50: 3 h 48 min from Bortle 6
- M109 with the ZWO Seestar S50 Pro: 4 h 10 min from Bortle 6
- M109 with the ZWO Seestar S30: 4 h from Bortle 6
- M109 with the ZWO Seestar S30 Pro: 4 h 25 min from Bortle 6
- M109 with the DwarfLab DWARF 3: 5 h 31 min from Bortle 6
- M109 with the DwarfLab DWARF mini: 3 h 47 min from Bortle 6
- M109 with the DwarfLab Draco: 3 h 07 min from Bortle 6
- M109 with the DwarfLab DWARF II: 13 h from Bortle 6
- M109 with the Vaonis Vespera II: 3 h 48 min from Bortle 6
- M109 with the Vaonis Vespera Pro: 8 h 31 min from Bortle 6
- M109 with the Vaonis Vespera 3: 3 h 38 min from Bortle 6
- M109 with the Vaonis Vespera Pro 2: 8 h 07 min from Bortle 6
- M109 with the Unistellar Odyssey: 16 h from Bortle 6
- M109 with the Celestron Origin: 1 h from Bortle 6
- M109 with the Celestron Origin Mark II: 1 h 23 min from Bortle 6