How long to image the M98 with the Celestron Origin

From a Bortle 6 suburban sky, the Celestron Origin needs about 1 h (362 subs of 10 s) for a solid image of the M98. A quick look takes 15 min; a showpiece 4 h 01 min. Under a Bortle 3 rural sky the solid figure drops to 20 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 19% of the frame’s short side.

M98 with the Celestron Origin: 10 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site4 min24 subs16 min96 subs1 h 03 min381 subs
Bortle 2Typical dark site4 min26 subs17 min104 subs1 h 09 min414 subs
Bortle 3Rural5 min30 subs20 min119 subs1 h 19 min476 subs
Bortle 4Rural / suburban transition7 min40 subs26 min157 subs1 h 44 min626 subs
Bortle 5Suburban9 min54 subs36 min216 subs2 h 24 min863 subs
Bortle 6Bright suburban15 min91 subs1 h362 subs4 h 01 min1,445 subs
Bortle 7Suburban / urban transition27 min160 subs1 h 46 min639 subs7 h 06 min2,555 subs
Bortle 8City45 min268 subs2 h 58 min1,070 subs12 h4,278 subs
Bortle 9Inner city1 h 23 min497 subs5 h 31 min1,988 subs22 h7,952 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 18 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 M98 is 9.5′ × 3.2′ across. The Origin frames 1.27° × 0.85° at 1.48″ per pixel, so it fills 19% 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 s20 min119 subs36 min216 subs1 h 46 min639 subs
15 s18 min74 subs35 min139 subs1 h 45 min421 subs
30 s17 min35 subs33 min67 subs1 h 44 min208 subs

About the M98

A nearly edge-on spiral in Coma, faint and elongated. Needs a dark sky or a long stack.

NGC 4192 · Galaxy in Coma Berenices · magnitude 10.1 · 9.5′ × 3.2′ · 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

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 M98 with your Origin? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M98 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 M98 · All targets for the Origin