How long to image the M32 with the DwarfLab DWARF II

From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 1 h 08 min (273 subs of 15 s) for a solid image of the M32. A quick look takes 17 min; a showpiece 4 h 32 min. Under a Bortle 3 rural sky the solid figure drops to 39 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 7% of the frame’s short side.

M32 with the DwarfLab DWARF II: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site9 min36 subs36 min143 subs2 h 23 min572 subs
Bortle 2Typical dark site9 min37 subs37 min147 subs2 h 27 min588 subs
Bortle 3Rural10 min39 subs39 min155 subs2 h 34 min618 subs
Bortle 4Rural / suburban transition11 min44 subs43 min173 subs2 h 53 min691 subs
Bortle 5Suburban13 min51 subs50 min202 subs3 h 21 min806 subs
Bortle 6Bright suburban17 min69 subs1 h 08 min273 subs4 h 32 min1,089 subs
Bortle 7Suburban / urban transition25 min102 subs1 h 42 min407 subs6 h 47 min1,628 subs
Bortle 8City38 min154 subs2 h 34 min616 subs10 h2,464 subs
Bortle 9Inner city1 h 06 min266 subs4 h 25 min1,062 subs18 h4,248 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 1 h 28 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 M32 is 8′ × 6′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 7% of the frame’s short side.

About the M32

The compact elliptical companion of Andromeda, sitting on its disc. Appears in every M31 frame.

NGC 221 · Galaxy in Andromeda · magnitude 8.1 · 8′ × 6′ · 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 M32 with your DWARF II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M32 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 M32 · All targets for the DWARF II