How long to image the M66 with the DwarfLab DWARF II

From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 2 h 18 min (553 subs of 15 s) for a solid image of the M66. A quick look takes 35 min; a showpiece 9 h 12 min. Under a Bortle 3 rural sky the solid figure drops to 1 h 14 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 8% of the frame’s short side.

M66 with the DwarfLab DWARF II: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site17 min68 subs1 h 08 min271 subs4 h 31 min1,083 subs
Bortle 2Typical dark site17 min70 subs1 h 10 min280 subs4 h 39 min1,118 subs
Bortle 3Rural18 min74 subs1 h 14 min296 subs4 h 56 min1,183 subs
Bortle 4Rural / suburban transition21 min84 subs1 h 24 min336 subs5 h 35 min1,342 subs
Bortle 5Suburban25 min100 subs1 h 40 min399 subs6 h 38 min1,593 subs
Bortle 6Bright suburban35 min139 subs2 h 18 min553 subs9 h 12 min2,210 subs
Bortle 7Suburban / urban transition53 min212 subs3 h 32 min847 subs14 h3,386 subs
Bortle 8City1 h 21 min326 subs5 h 26 min1,303 subs22 h5,212 subs
Bortle 9Inner city2 h 22 min570 subs9 h 29 min2,277 subs38 h9,105 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 3 h of run time. The DWARF II’s battery is rated at about 3 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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How it frames

The M66 is 9′ × 4′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 8% of the frame’s short side.

About the M66

The brightest of the Leo Triplet, with asymmetric arms from a past encounter.

NGC 3627 · Galaxy in Leo · magnitude 8.9 · 9′ × 4′ · best in Feb, Mar, Apr. 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 M66 with your DWARF II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the M66 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 M66 · All targets for the DWARF II