How long should I image the Abell 39 with the Origin from a Bortle 6 sky?

About 9 h 41 min of total integration for a solid image, or 39 h for a showpiece. A quick look takes 2 h 25 min.

How many subs is that on the Origin?

At the default 10 s sub length, 3,486 subs for a solid image from Bortle 6 and 1,032 from Bortle 3.

Does a dual-band filter help on the Abell 39?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 9 h 41 min to 4 h 38 min.

How long to image the Abell 39 with the Celestron Origin

From a Bortle 6 suburban sky, the Celestron Origin needs about 9 h 41 min (3,486 subs of 10 s) for a solid image of the Abell 39. A quick look takes 2 h 25 min; a showpiece 39 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 52 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 6% of the frame’s short side.

Abell 39 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	33 min199 subs	2 h 12 min793 subs	8 h 49 min3,172 subs
Bortle 2Typical dark site	36 min219 subs	2 h 26 min876 subs	9 h 44 min3,502 subs
Bortle 3Rural	43 min258 subs	2 h 52 min1,032 subs	11 h4,128 subs
Bortle 4Rural / suburban transition	59 min353 subs	3 h 55 min1,411 subs	16 h5,644 subs
Bortle 5Suburban	1 h 24 min503 subs	5 h 35 min2,012 subs	22 h8,047 subs
Bortle 6Bright suburban	2 h 25 min872 subs	9 h 41 min3,486 subs	39 h13,942 subs
Bortle 7Suburban / urban transition	4 h 22 min1,574 subs	17 h6,294 subs	70 h25,174 subs
Bortle 8City	7 h 24 min2,664 subs	30 h10,654 subs	120+ h42,615 subs
Bortle 9Inner city	14 h4,989 subs	55 h19,953 subs	220+ h79,810 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 13 h of run time. That is more than one night: over 2 nights, about 6 h 18 min each. The Origin’s battery is rated at about 6 h, so each night needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time.)

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How it frames

The Abell 39 is 2.9′ across. The Origin frames 1.27° × 0.85° at 1.48″ per pixel, so it fills 6% 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	2 h 52 min1,032 subs	5 h 35 min2,012 subs	17 h6,294 subs
15 s	2 h 38 min632 subs	5 h 21 min1,285 subs	17 h4,139 subs
30 s	2 h 24 min288 subs	5 h 07 min614 subs	17 h2,042 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	2 h 52 min1,032 subs	5 h 35 min2,012 subs	17 h6,294 subs
dual-band (Nebula Filter), drawer	2 h 33 min920 subs	3 h 23 min1,219 subs	7 h 02 min2,530 subs

The Origin has no built-in dual-band filter. Filter drawer takes 1.25-inch or 2-inch filters, including dual-band; Celestron sells an optional Nebula Filter. On an emission target like this it is the single biggest upgrade you can make.

About the Abell 39

A near-perfect faint sphere in Hercules. Very low surface brightness, an OIII target for dark skies and long dual-band stacks.

PN A66 39 · Planetary nebula in Hercules · magnitude 13.7 · 2.9′ · best in May, Jun, Jul. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.

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 Abell 39 with your Origin? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Abell 39 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 Abell 39 · All targets for the Origin