How long to image the M90 with the Celestron Origin Mark II

From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 55 min (331 subs of 10 s) for a solid image of the M90. A quick look takes 14 min; a showpiece 3 h 40 min. Under a Bortle 3 rural sky the solid figure drops to 17 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 21% of the frame’s short side.

M90 with the Celestron Origin Mark II: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site3 min20 subs13 min80 subs53 min318 subs
Bortle 2Typical dark site4 min22 subs15 min88 subs58 min349 subs
Bortle 3Rural4 min26 subs17 min102 subs1 h 08 min407 subs
Bortle 4Rural / suburban transition6 min35 subs23 min137 subs1 h 31 min548 subs
Bortle 5Suburban8 min49 subs32 min193 subs2 h 09 min772 subs
Bortle 6Bright suburban14 min83 subs55 min331 subs3 h 40 min1,321 subs
Bortle 7Suburban / urban transition25 min148 subs1 h 39 min592 subs6 h 35 min2,368 subs
Bortle 8City42 min250 subs2 h 46 min998 subs11 h3,992 subs
Bortle 9Inner city1 h 18 min467 subs5 h 11 min1,865 subs21 h7,457 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 12 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 M90 is 9.5′ × 4.5′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it fills 21% 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 s17 min102 subs32 min193 subs1 h 39 min592 subs
15 s17 min67 subs32 min128 subs1 h 38 min394 subs
30 s16 min33 subs31 min63 subs1 h 38 min196 subs

About the M90

A large spiral whose arms have been stripped by the cluster medium. Smooth and elongated.

NGC 4569 · Galaxy in Virgo · magnitude 9.5 · 9.5′ × 4.5′ · 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 M90 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 M90 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 M90 · All targets for the Origin Mark II