How long should I image the M4 with the Origin from a Bortle 6 sky?

About 20 min of total integration for a solid image, or 1 h 19 min for a showpiece. A quick look takes 5 min.

How many subs is that on the Origin?

At the default 10 s sub length, 119 subs for a solid image from Bortle 6 and 42 from Bortle 3.

Does a dual-band filter help on the M4?

No. The M4 is a broadband target and a dual-band filter blocks most of its light. Shoot without a filter.

How long to image the M4 with the Celestron Origin

From a Bortle 6 suburban sky, the Celestron Origin needs about 20 min (119 subs of 10 s) for a solid image of the M4. A quick look takes 5 min; a showpiece 1 h 19 min. Under a Bortle 3 rural sky the solid figure drops to 7 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 70% of the frame’s short side.

M4 with the Celestron Origin: 10 s subs.
Sky	Quick lookTarget obvious, still noisy	SolidClean enough to share	ShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site	2 min10 subs	6 min34 subs	22 min135 subs
Bortle 2Typical dark site	2 min10 subs	6 min37 subs	24 min146 subs
Bortle 3Rural	2 min11 subs	7 min42 subs	27 min165 subs
Bortle 4Rural / suburban transition	2 min14 subs	9 min54 subs	35 min213 subs
Bortle 5Suburban	3 min18 subs	12 min72 subs	48 min288 subs
Bortle 6Bright suburban	5 min30 subs	20 min119 subs	1 h 19 min473 subs
Bortle 7Suburban / urban transition	9 min52 subs	34 min207 subs	2 h 17 min825 subs
Bortle 8City	14 min86 subs	57 min343 subs	3 h 48 min1,371 subs
Bortle 9Inner city	26 min159 subs	1 h 46 min634 subs	7 h 03 min2,536 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 26 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 M4 is 36′ across. The Origin frames 1.27° × 0.85° at 1.48″ per pixel, so it fills 70% 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 length	Bortle 3	Bortle 5	Bortle 7
10 s	7 min42 subs	12 min72 subs	34 min207 subs
15 s	8 min30 subs	12 min47 subs	34 min136 subs
30 s	15 min30 subs	15 min30 subs	33 min67 subs

About the M4

The loose globular next to Antares. Low in the sky from the UK, so image it near transit.

NGC 6121 · Globular cluster in Scorpius · magnitude 5.9 · 36′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.

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 M4 with your Origin? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M4 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 M4 · All targets for the Origin