How long to image the De Mairan's Nebula with the Celestron Origin Mark II
From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 17 min (104 subs of 10 s) for a solid image of the De Mairan's Nebula. A quick look takes 4 min; a showpiece 1 h 09 min. Under a Bortle 3 rural sky the solid figure drops to 6 min. At Bortle 6 the limit is skyglow, so a darker site or a filter helps more than longer subs. In this scope's field it fills 45% 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 | 2 min10 subs | 5 min30 subs | 19 min113 subs |
| Bortle 2Typical dark site | 2 min10 subs | 5 min31 subs | 20 min122 subs |
| Bortle 3Rural | 2 min10 subs | 6 min35 subs | 23 min140 subs |
| Bortle 4Rural / suburban transition | 2 min12 subs | 8 min46 subs | 30 min182 subs |
| Bortle 5Suburban | 3 min16 subs | 10 min63 subs | 41 min249 subs |
| Bortle 6Bright suburban | 4 min26 subs | 17 min104 subs | 1 h 09 min414 subs |
| Bortle 7Suburban / urban transition | 8 min46 subs | 30 min182 subs | 2 h 01 min728 subs |
| Bortle 8City | 13 min76 subs | 51 min304 subs | 3 h 22 min1,215 subs |
| Bortle 9Inner city | 23 min141 subs | 1 h 34 min564 subs | 6 h 16 min2,254 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 22 min of run time. The Origin Mark II’s battery (rated about 6 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 December night.)
- portable power station 300W AC outletRuns the supplied 12 V adapter off-grid; dew shield and heater are built in.
- 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 Origin Mark II →
How it frames
The De Mairan's Nebula is 20′ × 15′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 45% of the frame’s short side.
Longer subs
10 s auto subs (15 s with the Nebula Filter); manual 1 to 30 s on the alt-az mount, longer only with the EQ wedge, and 60 s and up needs the StarSense Autoguider too. Celestron warns the f/2.2 optics saturate quickly without the filter. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 6 min35 subs | 10 min63 subs | 30 min182 subs |
| 15 s | 8 min30 subs | 10 min42 subs | 30 min121 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 30 min61 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 6 min35 subs | 10 min63 subs | 30 min182 subs |
| dual-band (Nebula Filter), drawer | 5 min32 subs | 7 min40 subs | 13 min77 subs |
The Origin Mark II has no built-in dual-band filter. Filter drawer takes 1.25-inch or 2-inch filters, including dual-band; Celestron sells an optional Nebula Filter. On an emission target like this it is the single biggest upgrade you can make.
About the De Mairan's Nebula
The comma-shaped nebula north of the Orion Nebula's core, split from it by a dark lane. Always in the same frame as M42.
M43, NGC 1982 · Emission nebula in Orion · magnitude 9.0 · 20′ × 15′ · best in Nov, Dec, Jan. 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 Celestron Origin Mark II
The Origin Mark II (late 2025): the same 6-inch f/2.2 RASA with an 8 MP IMX678 in place of the original 6 MP IMX178. Smaller pixels for finer detail, a quieter sensor, and still the fastest system here by a wide margin.
10 s auto subs (15 s with the Nebula Filter); manual 1 to 30 s on the alt-az mount, longer only with the EQ wedge, and 60 s and up needs the StarSense Autoguider too. Celestron warns the f/2.2 optics saturate quickly without the filter. Filter drawer takes 1.25-inch or 2-inch filters, including dual-band; Celestron sells an optional Nebula Filter.
Longer subs matter most under dark skies, where read noise rather than skyglow sets the floor. From a city the difference between 10 s and 30 s subs is small; from a rural site it can halve the total time, especially with a dual-band filter in place.
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 De Mairan's Nebula from a Origin Mark II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- De Mairan's Nebula with the ZWO Seestar S50: 32 min from Bortle 6
- De Mairan's Nebula with the ZWO Seestar S50 Pro: 35 min from Bortle 6
- De Mairan's Nebula with the ZWO Seestar S30: 36 min from Bortle 6
- De Mairan's Nebula with the ZWO Seestar S30 Pro: 38 min from Bortle 6
- De Mairan's Nebula with the DwarfLab DWARF 3: 40 min from Bortle 6
- De Mairan's Nebula with the DwarfLab DWARF mini: 31 min from Bortle 6
- De Mairan's Nebula with the DwarfLab Draco: 25 min from Bortle 6
- De Mairan's Nebula with the DwarfLab DWARF II: 2 h 41 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera II: 47 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera Pro: 1 h 46 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera 3: 45 min from Bortle 6
- De Mairan's Nebula with the Vaonis Vespera Pro 2: 1 h 41 min from Bortle 6
- De Mairan's Nebula with the Unistellar eQuinox 2: 42 min from Bortle 6
- De Mairan's Nebula with the Unistellar Odyssey: 3 h 15 min from Bortle 6
- De Mairan's Nebula with the Celestron Origin: 13 min from Bortle 6
All telescopes for the De Mairan's Nebula · All targets for the Origin Mark II