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

From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 1 h 39 min (395 subs of 15 s) for a solid image of the Sculptor Galaxy. A quick look takes 25 min; a showpiece 6 h 34 min. Under a Bortle 3 rural sky the solid figure drops to 52 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 25% of the frame’s short side.

Sculptor Galaxy with the DwarfLab DWARF II: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site12 min48 subs48 min191 subs3 h 11 min763 subs
Bortle 2Typical dark site12 min50 subs49 min197 subs3 h 17 min788 subs
Bortle 3Rural13 min53 subs52 min209 subs3 h 29 min836 subs
Bortle 4Rural / suburban transition15 min60 subs59 min238 subs3 h 57 min950 subs
Bortle 5Suburban18 min71 subs1 h 11 min283 subs4 h 43 min1,132 subs
Bortle 6Bright suburban25 min99 subs1 h 39 min395 subs6 h 34 min1,577 subs
Bortle 7Suburban / urban transition38 min152 subs2 h 32 min607 subs10 h2,426 subs
Bortle 8City58 min234 subs3 h 54 min936 subs16 h3,744 subs
Bortle 9Inner city1 h 42 min410 subs6 h 50 min1,639 subs27 h6,554 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 2 h 08 min of run time. The DWARF II’s battery (rated about 3 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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Everything that fits the DWARF II →

How it frames

The Sculptor Galaxy is 27′ × 7′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 25% of the frame’s short side.

About the Sculptor Galaxy

A big, dusty, nearly edge-on starburst galaxy, superb from the south and low but possible from mid-northern latitudes.

NGC 253, Caldwell 65, Silver Coin · Galaxy in Sculptor · magnitude 7.2 · 27′ × 7′ · best in Sep, Oct, Nov. 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 Sculptor 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 Sculptor 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 Sculptor Galaxy · All targets for the DWARF II