How long to image the Pinwheel Galaxy with the Celestron Origin

From a Bortle 6 suburban sky, the Celestron Origin needs about 1 h 13 min (439 subs of 10 s) for a solid image of the Pinwheel Galaxy. A quick look takes 18 min; a showpiece 4 h 52 min. Under a Bortle 3 rural sky the solid figure drops to 23 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 57% of the frame’s short side.

Pinwheel Galaxy with the Celestron Origin: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site5 min28 subs18 min109 subs1 h 12 min434 subs
Bortle 2Typical dark site5 min30 subs20 min119 subs1 h 19 min475 subs
Bortle 3Rural6 min35 subs23 min138 subs1 h 32 min551 subs
Bortle 4Rural / suburban transition8 min47 subs31 min185 subs2 h 03 min737 subs
Bortle 5Suburban11 min65 subs43 min258 subs2 h 52 min1,031 subs
Bortle 6Bright suburban18 min110 subs1 h 13 min439 subs4 h 52 min1,753 subs
Bortle 7Suburban / urban transition33 min196 subs2 h 10 min782 subs8 h 41 min3,128 subs
Bortle 8City55 min329 subs3 h 39 min1,316 subs15 h5,262 subs
Bortle 9Inner city1 h 42 min614 subs6 h 49 min2,454 subs27 h9,815 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 35 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.)

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How it frames

The Pinwheel Galaxy is 29′ × 27′ across. The Origin frames 1.27° × 0.85° at 1.48″ per pixel, so it fills 57% 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 lengthBortle 3Bortle 5Bortle 7
10 s23 min138 subs43 min258 subs2 h 10 min782 subs
15 s21 min85 subs41 min165 subs2 h 09 min515 subs
30 s19 min39 subs39 min79 subs2 h 07 min254 subs

About the Pinwheel Galaxy

Big, face-on and faint. Its total magnitude is flattering; spread over half a degree the arms are dim and demand hours, especially from suburban skies.

M101, NGC 5457 · Galaxy in Ursa Major · magnitude 7.9 · 29′ × 27′ · best in Apr, May, Jun. 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.

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Imaged the Pinwheel Galaxy with your Origin? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Pinwheel Galaxy from a Origin? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Pinwheel Galaxy · All targets for the Origin