How long to image the Spindle Galaxy with the Unistellar Odyssey

From a Bortle 6 suburban sky, the Unistellar Odyssey needs about 1 h 32 min (1,374 subs of 4 s) for a solid image of the Spindle Galaxy. A quick look takes 23 min; a showpiece 6 h 06 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 04 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 14% of the frame’s short side.

Spindle Galaxy with the Unistellar Odyssey: 4 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site15 min231 subs1 h 01 min922 subs4 h 06 min3,685 subs
Bortle 2Typical dark site16 min234 subs1 h 02 min935 subs4 h 09 min3,740 subs
Bortle 3Rural16 min241 subs1 h 04 min962 subs4 h 16 min3,845 subs
Bortle 4Rural / suburban transition17 min257 subs1 h 08 min1,025 subs4 h 33 min4,100 subs
Bortle 5Suburban19 min282 subs1 h 15 min1,126 subs5 h4,503 subs
Bortle 6Bright suburban23 min344 subs1 h 32 min1,374 subs6 h 06 min5,494 subs
Bortle 7Suburban / urban transition31 min462 subs2 h 03 min1,845 subs8 h 12 min7,380 subs
Bortle 8City43 min645 subs2 h 52 min2,578 subs11 h10,309 subs
Bortle 9Inner city1 h 09 min1,035 subs4 h 36 min4,139 subs18 h16,556 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 59 min of run time. The Odyssey’s battery (rated about 5 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 Spindle Galaxy is 4.7′ × 1.9′ across. The Odyssey frames 0.75° × 0.56° at 0.93″ per pixel, so it fills 14% of the frame’s short side.

About the Spindle Galaxy

An edge-on lenticular with a thin dust lane. Small, but its surface brightness is decent.

M102, NGC 5866 · Galaxy in Draco · magnitude 9.9 · 4.7′ × 1.9′ · best in Apr, May, Jun. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Galaxies are broadband targets: their light is mostly starlight spread across the spectrum, so a dual-band filter throws most of it away and makes things slower, not faster. Shoot without a filter (or with a plain UV/IR cut) and rely on total time and a dark sky. The core of a galaxy is usually many times brighter than its outer disc, so a short stack shows the nucleus long before the arms; the figures here are for the arms and disc, not the core.

Field rotation in Alt-Az mode crops the edges of the stack over a long session, so on a big galaxy re-centre now and then or use EQ mode where your scope supports it.

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

Have an image of the Spindle Galaxy 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 Spindle Galaxy · All targets for the Odyssey