How long to image the Thor's Helmet with the Celestron Origin Mark II
From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 3 h 44 min (1,345 subs of 10 s) for a solid image of the Thor's Helmet. A quick look takes 56 min; a showpiece 15 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 02 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 18% 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 | 11 min69 subs | 46 min276 subs | 3 h 03 min1,101 subs |
| Bortle 2Typical dark site | 13 min77 subs | 51 min308 subs | 3 h 25 min1,232 subs |
| Bortle 3Rural | 15 min93 subs | 1 h 02 min371 subs | 4 h 07 min1,481 subs |
| Bortle 4Rural / suburban transition | 22 min131 subs | 1 h 27 min521 subs | 5 h 47 min2,083 subs |
| Bortle 5Suburban | 32 min190 subs | 2 h 07 min760 subs | 8 h 26 min3,038 subs |
| Bortle 6Bright suburban | 56 min337 subs | 3 h 44 min1,345 subs | 15 h5,380 subs |
| Bortle 7Suburban / urban transition | 1 h 43 min616 subs | 6 h 50 min2,461 subs | 27 h9,844 subs |
| Bortle 8City | 2 h 55 min1,049 subs | 12 h4,194 subs | 47 h16,774 subs |
| Bortle 9Inner city | 5 h 29 min1,973 subs | 22 h7,889 subs | 88 h31,554 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 4 h 51 min of run time. The Origin Mark II’s battery is rated at about 6 h, less near freezing, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a January 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 Thor's Helmet is 8′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 18% 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 | 1 h 02 min371 subs | 2 h 07 min760 subs | 6 h 50 min2,461 subs |
| 15 s | 1 h241 subs | 2 h 05 min501 subs | 6 h 49 min1,635 subs |
| 30 s | 59 min118 subs | 2 h 04 min248 subs | 6 h 47 min815 subs |
With and without the dual-band filter
| Filter | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| No filter | 1 h 02 min371 subs | 2 h 07 min760 subs | 6 h 50 min2,461 subs |
| dual-band (Nebula Filter), drawer | 44 min266 subs | 1 h 04 min385 subs | 2 h 31 min906 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 Thor's Helmet
A Wolf-Rayet bubble with wings, strong in OIII. Small and faint; dual-band is essential and a bigger scope helps.
NGC 2359 · Emission nebula in Canis Major · magnitude 11.5 · 8′ · 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 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 Thor's Helmet 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
- Thor's Helmet with the ZWO Seestar S50: 6 h 17 min from Bortle 6
- Thor's Helmet with the ZWO Seestar S50 Pro: 7 h 04 min from Bortle 6
- Thor's Helmet with the ZWO Seestar S30: 7 h 24 min from Bortle 6
- Thor's Helmet with the ZWO Seestar S30 Pro: 7 h 38 min from Bortle 6
- Thor's Helmet with the DwarfLab DWARF 3: 7 h 41 min from Bortle 6
- Thor's Helmet with the DwarfLab DWARF mini: 6 h 11 min from Bortle 6
- Thor's Helmet with the DwarfLab Draco: 4 h 58 min from Bortle 6
- Thor's Helmet with the DwarfLab DWARF II: 36 h from Bortle 6
- Thor's Helmet with the Vaonis Vespera II: 10 h from Bortle 6
- Thor's Helmet with the Vaonis Vespera Pro: 23 h from Bortle 6
- Thor's Helmet with the Vaonis Vespera 3: 9 h 53 min from Bortle 6
- Thor's Helmet with the Vaonis Vespera Pro 2: 22 h from Bortle 6
- Thor's Helmet with the Unistellar eQuinox 2: 9 h 31 min from Bortle 6
- Thor's Helmet with the Unistellar Odyssey: 44 h from Bortle 6
- Thor's Helmet with the Celestron Origin: 2 h 44 min from Bortle 6
All telescopes for the Thor's Helmet · All targets for the Origin Mark II