How long to image the M54 with the Celestron Origin Mark II
From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 10 min (63 subs of 10 s) for a solid image of the M54. A quick look takes 3 min; a showpiece 42 min. Under a Bortle 3 rural sky the solid figure drops to 5 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 27% 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 | 15 min90 subs |
| Bortle 2Typical dark site | 2 min10 subs | 5 min30 subs | 15 min90 subs |
| Bortle 3Rural | 2 min10 subs | 5 min30 subs | 16 min95 subs |
| Bortle 4Rural / suburban transition | 2 min10 subs | 5 min30 subs | 20 min119 subs |
| Bortle 5Suburban | 2 min10 subs | 7 min40 subs | 26 min157 subs |
| Bortle 6Bright suburban | 3 min16 subs | 10 min63 subs | 42 min251 subs |
| Bortle 7Suburban / urban transition | 4 min27 subs | 18 min108 subs | 1 h 12 min430 subs |
| Bortle 8City | 7 min45 subs | 30 min178 subs | 1 h 58 min709 subs |
| Bortle 9Inner city | 14 min82 subs | 54 min326 subs | 3 h 37 min1,302 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 14 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 M54 is 12′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 27% 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 | 5 min30 subs | 7 min40 subs | 18 min108 subs |
| 15 s | 8 min30 subs | 8 min30 subs | 18 min72 subs |
| 30 s | 15 min30 subs | 15 min30 subs | 18 min36 subs |
About the M54
A globular that actually belongs to the Sagittarius Dwarf galaxy being eaten by the Milky Way. Low from the north.
NGC 6715 · Globular cluster in Sagittarius · magnitude 7.6 · 12′ · best in Jun, Jul, Aug. 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 M54 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
- M54 with the ZWO Seestar S50: 28 min from Bortle 6
- M54 with the ZWO Seestar S50 Pro: 31 min from Bortle 6
- M54 with the ZWO Seestar S30: 30 min from Bortle 6
- M54 with the ZWO Seestar S30 Pro: 33 min from Bortle 6
- M54 with the DwarfLab DWARF 3: 42 min from Bortle 6
- M54 with the DwarfLab DWARF mini: 28 min from Bortle 6
- M54 with the DwarfLab Draco: 23 min from Bortle 6
- M54 with the DwarfLab DWARF II: 1 h 36 min from Bortle 6
- M54 with the Vaonis Vespera II: 28 min from Bortle 6
- M54 with the Vaonis Vespera Pro: 1 h 03 min from Bortle 6
- M54 with the Vaonis Vespera 3: 27 min from Bortle 6
- M54 with the Vaonis Vespera Pro 2: 1 h 01 min from Bortle 6
- M54 with the Unistellar eQuinox 2: 25 min from Bortle 6
- M54 with the Unistellar Odyssey: 1 h 55 min from Bortle 6
- M54 with the Celestron Origin: 8 min from Bortle 6
All telescopes for the M54 · All targets for the Origin Mark II