How long to image the Monkey Head Nebula with the Unistellar eQuinox 2
From a Bortle 6 suburban sky, the Unistellar eQuinox 2 needs about 2 h 28 min (2,219 subs of 4 s) for a solid image of the Monkey Head Nebula. A quick look takes 37 min; a showpiece 9 h 52 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 25 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 1.2×.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 20 min295 subs | 1 h 18 min1,177 subs | 5 h 14 min4,707 subs |
| Bortle 2Typical dark site | 20 min303 subs | 1 h 21 min1,209 subs | 5 h 22 min4,835 subs |
| Bortle 3Rural | 21 min318 subs | 1 h 25 min1,270 subs | 5 h 38 min5,077 subs |
| Bortle 4Rural / suburban transition | 24 min354 subs | 1 h 34 min1,416 subs | 6 h 18 min5,664 subs |
| Bortle 5Suburban | 27 min413 subs | 1 h 50 min1,649 subs | 7 h 20 min6,593 subs |
| Bortle 6Bright suburban | 37 min555 subs | 2 h 28 min2,219 subs | 9 h 52 min8,874 subs |
| Bortle 7Suburban / urban transition | 55 min827 subs | 3 h 40 min3,305 subs | 15 h13,220 subs |
| Bortle 8City | 1 h 23 min1,248 subs | 5 h 33 min4,992 subs | 22 h19,967 subs |
| Bortle 9Inner city | 2 h 23 min2,148 subs | 9 h 33 min8,590 subs | 38 h34,358 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 12 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 Monkey Head Nebula is 40′ × 30′ across. The eQuinox 2 frames 0.76° × 0.57° at 1.33″ per pixel, so it is just over the frame at 1.2×. Point at the part you want; the edges will fall outside the frame.
Filters
The Monkey Head Nebula is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the eQuinox 2 has no dual-band option: 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 figures above are for the No filter position, and a darker sky is the lever that remains.
About the Monkey Head Nebula
A round emission cloud on the Orion-Gemini border with a profile like a monkey's face. Moderately bright, good with dual-band.
NGC 2174, Sh2-252 · Emission nebula in Orion · magnitude 6.8 · 40′ × 30′ · best in Dec, Jan, Feb. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.
Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.
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 Monkey Head Nebula from a eQuinox 2? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Monkey Head Nebula with the ZWO Seestar S50: 1 h 41 min from Bortle 6
- Monkey Head Nebula with the ZWO Seestar S50 Pro: 1 h 53 min from Bortle 6
- Monkey Head Nebula with the ZWO Seestar S30: 1 h 58 min from Bortle 6
- Monkey Head Nebula with the ZWO Seestar S30 Pro: 2 h 02 min from Bortle 6
- Monkey Head Nebula with the DwarfLab DWARF 3: 2 h 05 min from Bortle 6
- Monkey Head Nebula with the DwarfLab DWARF mini: 1 h 40 min from Bortle 6
- Monkey Head Nebula with the DwarfLab Draco: 1 h 20 min from Bortle 6
- Monkey Head Nebula with the DwarfLab DWARF II: 9 h 16 min from Bortle 6
- Monkey Head Nebula with the Vaonis Vespera II: 2 h 42 min from Bortle 6
- Monkey Head Nebula with the Vaonis Vespera Pro: 6 h 03 min from Bortle 6
- Monkey Head Nebula with the Vaonis Vespera 3: 2 h 35 min from Bortle 6
- Monkey Head Nebula with the Vaonis Vespera Pro 2: 5 h 46 min from Bortle 6
- Monkey Head Nebula with the Unistellar Odyssey: 11 h from Bortle 6
- Monkey Head Nebula with the Celestron Origin: 43 min from Bortle 6
- Monkey Head Nebula with the Celestron Origin Mark II: 59 min from Bortle 6
All telescopes for the Monkey Head Nebula · All targets for the eQuinox 2