How long to image the M72 with the Celestron Origin Mark II
From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 26 min (157 subs of 10 s) for a solid image of the M72. A quick look takes 7 min; a showpiece 1 h 44 min. Under a Bortle 3 rural sky the solid figure drops to 9 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 13% 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 min12 subs | 8 min47 subs | 31 min185 subs |
| Bortle 2Typical dark site | 2 min13 subs | 8 min50 subs | 33 min198 subs |
| Bortle 3Rural | 2 min14 subs | 9 min56 subs | 37 min224 subs |
| Bortle 4Rural / suburban transition | 3 min18 subs | 12 min72 subs | 48 min286 subs |
| Bortle 5Suburban | 4 min25 subs | 16 min97 subs | 1 h 04 min385 subs |
| Bortle 6Bright suburban | 7 min40 subs | 26 min157 subs | 1 h 44 min627 subs |
| Bortle 7Suburban / urban transition | 11 min69 subs | 45 min273 subs | 3 h 01 min1,089 subs |
| Bortle 8City | 19 min113 subs | 1 h 15 min452 subs | 5 h 01 min1,806 subs |
| Bortle 9Inner city | 35 min209 subs | 2 h 19 min834 subs | 9 h 16 min3,334 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 34 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.)
- 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.
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Everything that fits the Origin Mark II →
How it frames
The M72 is 6′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 13% 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 | 9 min56 subs | 16 min97 subs | 45 min273 subs |
| 15 s | 9 min37 subs | 16 min64 subs | 45 min181 subs |
| 30 s | 15 min30 subs | 16 min32 subs | 45 min91 subs |
About the M72
A faint, distant globular in Aquarius. Among the harder Messier globulars.
NGC 6981 · Globular cluster in Aquarius · magnitude 9.3 · 6′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.
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 M72 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
- M72 with the ZWO Seestar S50: 1 h 11 min from Bortle 6
- M72 with the ZWO Seestar S50 Pro: 1 h 18 min from Bortle 6
- M72 with the ZWO Seestar S30: 1 h 15 min from Bortle 6
- M72 with the ZWO Seestar S30 Pro: 1 h 23 min from Bortle 6
- M72 with the DwarfLab DWARF 3: 1 h 44 min from Bortle 6
- M72 with the DwarfLab DWARF mini: 1 h 11 min from Bortle 6
- M72 with the DwarfLab Draco: 59 min from Bortle 6
- M72 with the DwarfLab DWARF II: 4 h 02 min from Bortle 6
- M72 with the Vaonis Vespera II: 1 h 11 min from Bortle 6
- M72 with the Vaonis Vespera Pro: 2 h 39 min from Bortle 6
- M72 with the Vaonis Vespera 3: 1 h 08 min from Bortle 6
- M72 with the Vaonis Vespera Pro 2: 2 h 32 min from Bortle 6
- M72 with the Unistellar eQuinox 2: 1 h 04 min from Bortle 6
- M72 with the Unistellar Odyssey: 4 h 51 min from Bortle 6
- M72 with the Celestron Origin: 19 min from Bortle 6
All telescopes for the M72 · All targets for the Origin Mark II