How long should I image the Witch Head Nebula with the Origin Mark II from a Bortle 6 sky?

About 15 h of total integration for a solid image, or 58 h for a showpiece. A quick look takes 3 h 39 min.

How many subs is that on the Origin Mark II?

At the default 10 s sub length, 5,259 subs for a solid image from Bortle 6 and 1,315 from Bortle 3.

Does a dual-band filter help on the Witch Head Nebula?

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

How long to image the Witch Head Nebula with the Celestron Origin Mark II

From a Bortle 6 suburban sky, the Celestron Origin Mark II needs about 15 h (5,259 subs of 10 s) for a solid image of the Witch Head Nebula. A quick look takes 3 h 39 min; a showpiece 58 h. Under a Bortle 3 rural sky the solid figure drops to 3 h 39 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 4.0× wider than the frame.

Witch Head 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	39 min233 subs	2 h 35 min931 subs	10 h3,721 subs
Bortle 2Typical dark site	44 min266 subs	2 h 57 min1,064 subs	12 h4,253 subs
Bortle 3Rural	55 min329 subs	3 h 39 min1,315 subs	15 h5,259 subs
Bortle 4Rural / suburban transition	1 h 20 min481 subs	5 h 21 min1,924 subs	21 h7,696 subs
Bortle 5Suburban	2 h723 subs	8 h 02 min2,890 subs	32 h11,559 subs
Bortle 6Bright suburban	3 h 39 min1,315 subs	15 h5,259 subs	58 h21,036 subs
Bortle 7Suburban / urban transition	6 h 47 min2,444 subs	27 h9,774 subs	110+ h39,093 subs
Bortle 8City	12 h4,196 subs	47 h16,783 subs	190+ h67,130 subs
Bortle 9Inner city	22 h7,933 subs	88 h31,732 subs	350+ h126,925 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 19 h of run time. That is more than one night: over 3 nights, about 6 h 20 min each. The Origin Mark II’s battery is rated at about 6 h, less near freezing, so each night needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a December night.)

portable power station 300W AC outletRuns the supplied 12 V adapter off-grid; dew shield and heater are built in.
Amazon UK Amazon US Jackery UK
red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
Amazon UK Amazon US
hand warmers long lastingAir-activated packs give hours of heat for the person; winter nights are long and you spend most of them standing still.
Amazon UK Amazon US

Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.

Everything that fits the Origin Mark II →

How it frames

The Witch Head Nebula is 180′ × 60′ across. The Origin Mark II frames 1.32° × 0.75° at 1.23″ per pixel, so it is 4.0× wider than the frame. A mosaic, or choosing the part you want and letting the rest go, is how it gets shot on this scope.

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	3 h 39 min1,315 subs	8 h 02 min2,890 subs	27 h9,774 subs
15 s	3 h 33 min853 subs	7 h 56 min1,903 subs	27 h6,492 subs
30 s	3 h 27 min415 subs	7 h 50 min940 subs	27 h3,234 subs

About the Witch Head Nebula

A very faint blue reflection nebula lit by Rigel. A dark-sky, all-night, broadband project; it is one of the hardest objects on this list.

IC 2118 · Reflection nebula in Eridanus · magnitude 13.0 · 180′ × 60′ · best in Nov, Dec, Jan. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Reflection nebulae are starlight scattered by dust, so they are broadband and blue. A dual-band filter removes almost all of it; do not use one. These are among the faintest structures a smart scope can attempt and the figures run long. A dark sky matters more here than for any other type, and the Moon must be down.

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 Witch Head 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 Witch Head 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 Witch Head Nebula · All targets for the Origin Mark II