How long to image the Black Eye Galaxy with the Celestron Origin Mark II

From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 13 min (76 subs of 10 s) for a solid image of the Black Eye Galaxy. A quick look takes 3 min; a showpiece 50 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 22% of the frame’s short side.

Black Eye 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 min10 subs5 min30 subs16 min96 subs
Bortle 2Typical dark site2 min10 subs5 min30 subs17 min102 subs
Bortle 3Rural2 min10 subs5 min30 subs19 min114 subs
Bortle 4Rural / suburban transition2 min10 subs6 min36 subs24 min143 subs
Bortle 5Suburban2 min12 subs8 min48 subs31 min189 subs
Bortle 6Bright suburban3 min19 subs13 min76 subs50 min302 subs
Bortle 7Suburban / urban transition5 min33 subs22 min130 subs1 h 26 min518 subs
Bortle 8City9 min54 subs35 min213 subs2 h 22 min852 subs
Bortle 9Inner city16 min98 subs1 h 05 min392 subs4 h 21 min1,566 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 16 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 Black Eye Galaxy is 10′ × 5′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 22% 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 s5 min30 subs8 min48 subs22 min130 subs
15 s8 min30 subs8 min32 subs21 min86 subs
30 s15 min30 subs15 min30 subs21 min43 subs

About the Black Eye Galaxy

A bright spiral with a dark dust band across the nucleus. The eye shows within an hour on a 50 mm scope.

M64, NGC 4826 · Galaxy in Coma Berenices · magnitude 8.5 · 10′ × 5′ · 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 Black Eye 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 Black Eye 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 Black Eye Galaxy · All targets for the Origin Mark II