How long to image the Eagle Nebula with the Unistellar Odyssey

From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 6 h 39 min (5,992 subs of 4 s) for a solid image of the Eagle Nebula. A quick look takes 1 h 40 min; a showpiece 27 h. Under a Bortle 3 rural sky the solid figure drops to 4 h 27 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is just over the frame at 1.0×.

Eagle Nebula with the Unistellar Odyssey: 4 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site1 h 04 min953 subs4 h 14 min3,811 subs17 h15,242 subs
Bortle 2Typical dark site1 h 05 min970 subs4 h 18 min3,878 subs17 h15,510 subs
Bortle 3Rural1 h 07 min1,002 subs4 h 27 min4,005 subs18 h16,017 subs
Bortle 4Rural / suburban transition1 h 12 min1,078 subs4 h 47 min4,312 subs19 h17,245 subs
Bortle 5Suburban1 h 20 min1,200 subs5 h 20 min4,798 subs21 h19,191 subs
Bortle 6Bright suburban1 h 40 min1,498 subs6 h 39 min5,992 subs27 h23,966 subs
Bortle 7Suburban / urban transition2 h 18 min2,067 subs9 h 11 min8,267 subs37 h33,065 subs
Bortle 8City3 h 17 min2,950 subs13 h11,798 subs52 h47,192 subs
Bortle 9Inner city5 h 22 min4,833 subs21 h19,331 subs86 h77,321 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 8 h 39 min of run time. That is more than one night: over 2 nights, about 4 h 20 min each. The Odyssey’s battery is rated at about 5 h, which is cutting it fine; take a power bank. (Bortle 6, solid image; we allow 30% over the integration time.)

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Everything that fits the Odyssey →

How it frames

The Eagle Nebula is 35′ × 28′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it is just over the frame at 1.0×. Point at the part you want; the edges will fall outside the frame.

Filters

The Eagle Nebula is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the Odyssey has no dual-band option: No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey. The figures above are for the No filter position, and a darker sky is the lever that remains.

About the Eagle Nebula

Home of the Pillars of Creation. The cluster comes fast; the pillars and surrounding nebulosity need a dual-band filter and patience.

M16, NGC 6611, IC 4703 · Emission nebula in Serpens · magnitude 6.0 · 35′ × 28′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Emission nebulae glow in a few narrow lines, mostly hydrogen-alpha (deep red) and doubly ionised oxygen (teal). A dual-band filter passes those lines and blocks most skyglow, which is why it cuts the time needed from a suburban sky so dramatically. Use it. From a genuinely dark site the gain is smaller because there is less skyglow to block, and read noise becomes the limit, which is where longer subs (EQ mode, or Expert Mode on a Vespera) earn their keep.

Stars lose colour through a dual-band filter; a short broadband stack blended in fixes that if you care.

About the Unistellar Odyssey

Unistellar’s compact 85 mm with autofocus and tiny pixels. Sharp, but the fine sampling costs time on faint extended targets. The Odyssey Pro is the same telescope with an eyepiece added, so these figures apply to both.

Fixed 4 s subs in Enhanced Vision; they cannot be changed. No filter option; Unistellar says third-party filters cannot be fitted to the Odyssey.

The Odyssey uses fixed 4 s subs, so the only levers you have are the sky you shoot from, the filter, and total time.

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 Eagle Nebula with your Odyssey? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Eagle Nebula from a Odyssey? Email it with your total time and sky to [email protected] and it goes here, credited.

Same target, other telescopes

All telescopes for the Eagle Nebula · All targets for the Odyssey