How long should I image the Bow-Tie Nebula with the Origin Mark II from a Bortle 6 sky?

About 10 min of total integration for a solid image, or 41 min for a showpiece. A quick look takes 3 min.

How many subs is that on the Origin Mark II?

At the default 10 s sub length, 61 subs for a solid image from Bortle 6 and 30 from Bortle 3.

Does a dual-band filter help on the Bow-Tie Nebula?

Yes. It is an emission-line object; from Bortle 6 the filter cuts the solid-image time from 10 min to 6 min.

How long to image the Bow-Tie Nebula with the Celestron Origin Mark II

From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 10 min (61 subs of 10 s) for a solid image of the Bow-Tie Nebula. A quick look takes 3 min; a showpiece 41 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 is small in the frame, about 39 pixels across.

Bow-Tie Nebula with the Celestron Origin Mark II: 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	5 min30 subs	15 min90 subs
Bortle 2Typical dark site	2 min10 subs	5 min30 subs	16 min94 subs
Bortle 3Rural	2 min10 subs	5 min30 subs	17 min103 subs
Bortle 4Rural / suburban transition	2 min10 subs	5 min32 subs	21 min125 subs
Bortle 5Suburban	2 min10 subs	7 min40 subs	26 min159 subs
Bortle 6Bright suburban	3 min16 subs	10 min61 subs	41 min244 subs
Bortle 7Suburban / urban transition	4 min26 subs	17 min102 subs	1 h 08 min406 subs
Bortle 8City	7 min42 subs	27 min165 subs	1 h 49 min657 subs
Bortle 9Inner city	12 min75 subs	50 min299 subs	3 h 19 min1,193 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 13 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 Bow-Tie Nebula is 0.8′ × 0.6′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it is small in the frame, about 39 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.

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 length	Bortle 3	Bortle 5	Bortle 7
10 s	5 min30 subs	7 min40 subs	17 min102 subs
15 s	8 min30 subs	8 min30 subs	17 min68 subs
30 s	15 min30 subs	15 min30 subs	17 min34 subs

With and without the dual-band filter

Solid quality, default sub length.
Filter	Bortle 3	Bortle 5	Bortle 7
No filter	5 min30 subs	7 min40 subs	17 min102 subs
dual-band (Nebula Filter), drawer	5 min30 subs	5 min32 subs	8 min51 subs

The Origin Mark II 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 Bow-Tie Nebula

A red-tinged planetary near the pole with a bright central star. Small; dual-band brings out the bow.

NGC 40, Caldwell 2 · Planetary nebula in Cepheus · magnitude 11.6 · 0.8′ × 0.6′ · best in Sep, Oct, Nov. 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 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.

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.

Where to buy the Origin Mark IICelestron store Direct Amazon UK Amazon USThe Celestron store link is a plain link; the others are affiliate links. As an Amazon Associate I earn from qualifying purchases, at no cost to you.

Imaged the Bow-Tie Nebula 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 Bow-Tie Nebula 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 Bow-Tie Nebula · All targets for the Origin Mark II