How long to image the M99 with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 2 h 32 min (2,280 subs of 4 s) for a solid image of the M99. A quick look takes 38 min; a showpiece 10 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 28 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 16% 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 | 21 min309 subs | 1 h 22 min1,233 subs | 5 h 29 min4,930 subs |
| Bortle 2Typical dark site | 21 min317 subs | 1 h 24 min1,265 subs | 5 h 37 min5,059 subs |
| Bortle 3Rural | 22 min332 subs | 1 h 28 min1,326 subs | 5 h 53 min5,302 subs |
| Bortle 4Rural / suburban transition | 25 min369 subs | 1 h 38 min1,473 subs | 6 h 33 min5,892 subs |
| Bortle 5Suburban | 28 min427 subs | 1 h 54 min1,707 subs | 7 h 35 min6,826 subs |
| Bortle 6Bright suburban | 38 min570 subs | 2 h 32 min2,280 subs | 10 h9,119 subs |
| Bortle 7Suburban / urban transition | 56 min843 subs | 3 h 45 min3,372 subs | 15 h13,487 subs |
| Bortle 8City | 1 h 24 min1,267 subs | 5 h 38 min5,068 subs | 23 h20,270 subs |
| Bortle 9Inner city | 2 h 25 min2,171 subs | 9 h 39 min8,684 subs | 39 h34,735 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 18 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 M99 is 5.4′ × 4.8′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it fills 16% of the frame’s short side.
About the M99
A face-on spiral with one arm flung out by an encounter. Small but distinctive.
NGC 4254, Coma Pinwheel · Galaxy in Coma Berenices · magnitude 9.9 · 5.4′ × 4.8′ · best in Mar, Apr, May. 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 M99 from a eQuinox 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M99 with the ZWO Seestar S50: 2 h 48 min from Bortle 6
- M99 with the ZWO Seestar S50 Pro: 3 h 04 min from Bortle 6
- M99 with the ZWO Seestar S30: 2 h 56 min from Bortle 6
- M99 with the ZWO Seestar S30 Pro: 3 h 15 min from Bortle 6
- M99 with the DwarfLab DWARF 3: 4 h 04 min from Bortle 6
- M99 with the DwarfLab DWARF mini: 2 h 47 min from Bortle 6
- M99 with the DwarfLab Draco: 2 h 18 min from Bortle 6
- M99 with the DwarfLab DWARF II: 9 h 34 min from Bortle 6
- M99 with the Vaonis Vespera II: 2 h 48 min from Bortle 6
- M99 with the Vaonis Vespera Pro: 6 h 16 min from Bortle 6
- M99 with the Vaonis Vespera 3: 2 h 40 min from Bortle 6
- M99 with the Vaonis Vespera Pro 2: 5 h 58 min from Bortle 6
- M99 with the Unistellar Odyssey: 12 h from Bortle 6
- M99 with the Celestron Origin: 44 min from Bortle 6
- M99 with the Celestron Origin Mark II: 1 h 01 min from Bortle 6