How long to image the M99 with the Celestron Origin
From a Bortle 6 suburban sky, the Celestron Origin needs about 44 min (267 subs of 10 s) for a solid image of the M99. A quick look takes 11 min; a showpiece 2 h 58 min. Under a Bortle 3 rural sky the solid figure drops to 16 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 11% 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 min20 subs | 13 min77 subs | 51 min305 subs |
| Bortle 2Typical dark site | 3 min21 subs | 14 min83 subs | 55 min329 subs |
| Bortle 3Rural | 4 min24 subs | 16 min94 subs | 1 h 02 min373 subs |
| Bortle 4Rural / suburban transition | 5 min30 subs | 20 min120 subs | 1 h 20 min480 subs |
| Bortle 5Suburban | 7 min41 subs | 27 min163 subs | 1 h 48 min650 subs |
| Bortle 6Bright suburban | 11 min67 subs | 44 min267 subs | 2 h 58 min1,068 subs |
| Bortle 7Suburban / urban transition | 19 min117 subs | 1 h 18 min466 subs | 5 h 10 min1,863 subs |
| Bortle 8City | 32 min194 subs | 2 h 09 min775 subs | 8 h 36 min3,098 subs |
| Bortle 9Inner city | 1 h359 subs | 3 h 59 min1,433 subs | 16 h5,731 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 58 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 M99 is 5.4′ × 4.8′ across. The Origin frames 1.27° × 0.85° at 1.48″ per pixel, so it fills 11% 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 | 16 min94 subs | 27 min163 subs | 1 h 18 min466 subs |
| 15 s | 15 min59 subs | 26 min105 subs | 1 h 17 min307 subs |
| 30 s | 15 min30 subs | 25 min51 subs | 1 h 16 min152 subs |
About the M99
A face-on spiral with one arm flung out by an encounter. Small but distinctive.
NGC 4254, Coma Pinwheel · Galaxy in Coma Berenices · magnitude 9.9 · 5.4′ × 4.8′ · 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 M99 from a Origin? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M99 with the ZWO Seestar S50: 2 h 48 min from Bortle 6
- M99 with the ZWO Seestar S50 Pro: 3 h 04 min from Bortle 6
- M99 with the ZWO Seestar S30: 2 h 56 min from Bortle 6
- M99 with the ZWO Seestar S30 Pro: 3 h 15 min from Bortle 6
- M99 with the DwarfLab DWARF 3: 4 h 04 min from Bortle 6
- M99 with the DwarfLab DWARF mini: 2 h 47 min from Bortle 6
- M99 with the DwarfLab Draco: 2 h 18 min from Bortle 6
- M99 with the DwarfLab DWARF II: 9 h 34 min from Bortle 6
- M99 with the Vaonis Vespera II: 2 h 48 min from Bortle 6
- M99 with the Vaonis Vespera Pro: 6 h 16 min from Bortle 6
- M99 with the Vaonis Vespera 3: 2 h 40 min from Bortle 6
- M99 with the Vaonis Vespera Pro 2: 5 h 58 min from Bortle 6
- M99 with the Unistellar eQuinox 2: 2 h 32 min from Bortle 6
- M99 with the Unistellar Odyssey: 12 h from Bortle 6
- M99 with the Celestron Origin Mark II: 1 h 01 min from Bortle 6