How long to image the Cigar Galaxy with the DwarfLab DWARF II

From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 1 h 57 min (467 subs of 15 s) for a solid image of the Cigar Galaxy. A quick look takes 29 min; a showpiece 7 h 46 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 02 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 10% of the frame’s short side.

Cigar Galaxy with the DwarfLab DWARF II: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site14 min57 subs57 min228 subs3 h 48 min912 subs
Bortle 2Typical dark site15 min59 subs59 min236 subs3 h 55 min941 subs
Bortle 3Rural16 min63 subs1 h 02 min250 subs4 h 09 min997 subs
Bortle 4Rural / suburban transition18 min71 subs1 h 11 min283 subs4 h 43 min1,131 subs
Bortle 5Suburban21 min84 subs1 h 24 min336 subs5 h 36 min1,343 subs
Bortle 6Bright suburban29 min117 subs1 h 57 min467 subs7 h 46 min1,865 subs
Bortle 7Suburban / urban transition45 min179 subs2 h 59 min715 subs12 h2,859 subs
Bortle 8City1 h 09 min276 subs4 h 35 min1,101 subs18 h4,403 subs
Bortle 9Inner city2 h481 subs8 h 01 min1,924 subs32 h7,695 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 2 h 32 min of run time. The DWARF II’s battery is rated at about 3 h, less near freezing, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a February night.)

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How it frames

The Cigar Galaxy is 11′ × 4′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 10% of the frame’s short side.

About the Cigar Galaxy

An edge-on starburst galaxy with red hydrogen jets bursting from its core. Dual-band pulls the jets out of the glare.

M82, NGC 3034 · Galaxy in Ursa Major · magnitude 8.4 · 11′ × 4′ · best in Jan, Feb, Mar. 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 DwarfLab DWARF II

The original pocket scope. 24 mm aperture and tiny 1.45 µm pixels mean it is slow per pixel, so bin or downsample and be patient.

15 s is the hard maximum in any mode; DwarfLab recommends EQ mode at 15 s. Two built-in filters, VIS and Astro (IR-pass); no dual-band. The optional UHC filter is no longer sold.

The DWARF II uses fixed 15 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 Cigar Galaxy with your DWARF II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Cigar Galaxy from a DWARF 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 Cigar Galaxy · All targets for the DWARF II