How long to image the M100 with the Celestron Origin
From a Bortle 6 suburban sky, the Celestron Origin needs about 37 min (223 subs of 10 s) for a solid image of the M100. A quick look takes 9 min; a showpiece 2 h 28 min. Under a Bortle 3 rural sky the solid figure drops to 13 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 14% 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 | 3 min17 subs | 11 min65 subs | 43 min259 subs |
| Bortle 2Typical dark site | 3 min18 subs | 12 min70 subs | 46 min279 subs |
| Bortle 3Rural | 3 min20 subs | 13 min79 subs | 52 min315 subs |
| Bortle 4Rural / suburban transition | 4 min26 subs | 17 min101 subs | 1 h 07 min404 subs |
| Bortle 5Suburban | 6 min35 subs | 23 min137 subs | 1 h 31 min545 subs |
| Bortle 6Bright suburban | 9 min56 subs | 37 min223 subs | 2 h 28 min891 subs |
| Bortle 7Suburban / urban transition | 16 min97 subs | 1 h 05 min388 subs | 4 h 18 min1,549 subs |
| Bortle 8City | 27 min161 subs | 1 h 47 min643 subs | 7 h 09 min2,572 subs |
| Bortle 9Inner city | 49 min297 subs | 3 h 18 min1,188 subs | 13 h4,752 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 48 min of run time. The Origin’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 in the field; the dew shield and heater are already 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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How it frames
The M100 is 7′ × 6′ across. The Origin frames 1.27° × 0.85° at 1.48″ per pixel, so it fills 14% 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. Time for a solid image by sub length:
| Sub length | Bortle 3 | Bortle 5 | Bortle 7 |
|---|---|---|---|
| 10 s | 13 min79 subs | 23 min137 subs | 1 h 05 min388 subs |
| 15 s | 12 min50 subs | 22 min88 subs | 1 h 04 min255 subs |
| 30 s | 15 min30 subs | 21 min43 subs | 1 h 03 min126 subs |
About the M100
A grand-design spiral in Coma Berenices, one of the biggest in the Virgo cluster.
NGC 4321 · Galaxy in Coma Berenices · magnitude 9.3 · 7′ × 6′ · best in Mar, Apr, May. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.
Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.
About the Celestron Origin
The first-generation Origin: a 6-inch f/2.2 RASA in a smart package and the fastest system here by a wide margin. Superseded by the Mark II in late 2025 and no longer sold new; Celestron offers a camera upgrade to the Mark II sensor.
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. 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 M100 from a Origin? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M100 with the ZWO Seestar S50: 2 h 20 min from Bortle 6
- M100 with the ZWO Seestar S50 Pro: 2 h 33 min from Bortle 6
- M100 with the ZWO Seestar S30: 2 h 27 min from Bortle 6
- M100 with the ZWO Seestar S30 Pro: 2 h 42 min from Bortle 6
- M100 with the DwarfLab DWARF 3: 3 h 24 min from Bortle 6
- M100 with the DwarfLab DWARF mini: 2 h 19 min from Bortle 6
- M100 with the DwarfLab Draco: 1 h 55 min from Bortle 6
- M100 with the DwarfLab DWARF II: 7 h 58 min from Bortle 6
- M100 with the Vaonis Vespera II: 2 h 20 min from Bortle 6
- M100 with the Vaonis Vespera Pro: 5 h 13 min from Bortle 6
- M100 with the Vaonis Vespera 3: 2 h 14 min from Bortle 6
- M100 with the Vaonis Vespera Pro 2: 4 h 59 min from Bortle 6
- M100 with the Unistellar eQuinox 2: 2 h 06 min from Bortle 6
- M100 with the Unistellar Odyssey: 9 h 43 min from Bortle 6
- M100 with the Celestron Origin Mark II: 51 min from Bortle 6