How long to image the Sunflower Galaxy with the Celestron Origin Mark II

From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 36 min (216 subs of 10 s) for a solid image of the Sunflower Galaxy. A quick look takes 9 min; a showpiece 2 h 24 min. Under a Bortle 3 rural sky the solid figure drops to 11 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 28% of the frame’s short side.

Sunflower Galaxy with the Celestron Origin Mark II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site2 min14 subs9 min53 subs35 min212 subs
Bortle 2Typical dark site2 min15 subs10 min58 subs39 min232 subs
Bortle 3Rural3 min17 subs11 min68 subs45 min270 subs
Bortle 4Rural / suburban transition4 min23 subs15 min91 subs1 h361 subs
Bortle 5Suburban5 min32 subs21 min127 subs1 h 24 min506 subs
Bortle 6Bright suburban9 min54 subs36 min216 subs2 h 24 min862 subs
Bortle 7Suburban / urban transition16 min97 subs1 h 04 min385 subs4 h 16 min1,538 subs
Bortle 8City27 min162 subs1 h 48 min648 subs7 h 12 min2,590 subs
Bortle 9Inner city50 min302 subs3 h 21 min1,208 subs13 h4,831 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 47 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.)

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How it frames

The Sunflower Galaxy is 12.6′ × 7.2′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 28% 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 lengthBortle 3Bortle 5Bortle 7
10 s11 min68 subs21 min127 subs1 h 04 min385 subs
15 s11 min45 subs21 min84 subs1 h 04 min256 subs
30 s15 min30 subs21 min42 subs1 h 04 min128 subs

About the Sunflower Galaxy

A flocculent spiral whose arms break into patches like sunflower seeds. Bright core, subtle outer disc.

M63, NGC 5055 · Galaxy in Canes Venatici · magnitude 8.6 · 12.6′ × 7.2′ · 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 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.

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

Have an image of the Sunflower Galaxy 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

All telescopes for the Sunflower Galaxy · All targets for the Origin Mark II