How long to image the Ghost of Jupiter with the DwarfLab DWARF II

From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 40 min (162 subs of 15 s) for a solid image of the Ghost of Jupiter. A quick look takes 10 min; a showpiece 2 h 41 min. Under a Bortle 3 rural sky the solid figure drops to 24 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it is small in the frame, about 8 pixels across.

Ghost of Jupiter with the DwarfLab DWARF II: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site6 min23 subs23 min92 subs1 h 31 min366 subs
Bortle 2Typical dark site6 min24 subs23 min94 subs1 h 34 min375 subs
Bortle 3Rural6 min25 subs24 min98 subs1 h 38 min391 subs
Bortle 4Rural / suburban transition7 min27 subs27 min108 subs1 h 47 min430 subs
Bortle 5Suburban8 min31 subs31 min124 subs2 h 03 min493 subs
Bortle 6Bright suburban10 min41 subs40 min162 subs2 h 41 min646 subs
Bortle 7Suburban / urban transition15 min59 subs59 min235 subs3 h 54 min938 subs
Bortle 8City22 min87 subs1 h 27 min348 subs5 h 48 min1,391 subs
Bortle 9Inner city37 min148 subs2 h 27 min590 subs9 h 49 min2,358 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 52 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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How it frames

The Ghost of Jupiter is 0.42′ × 0.35′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it is small in the frame, about 8 pixels across. It is worth doing, but the result is a crop rather than a full frame; a longer focal length would resolve more of it.

Filters

The Ghost of Jupiter is an emission target, where a dual-band filter would normally cut the time several-fold from a lit sky, but the DWARF II has no dual-band option: Two built-in filters, VIS and Astro (IR-pass); no dual-band. The optional UHC filter is no longer sold. The figures above are for the Astro position, and a darker sky is the lever that remains.

About the Ghost of Jupiter

A bright, blue-green planetary the apparent size of Jupiter. Very bright per pixel; keep subs short.

NGC 3242, Caldwell 59 · Planetary nebula in Hydra · magnitude 7.7 · 0.42′ × 0.35′ · best in Feb, Mar, Apr. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Planetary nebulae are small but intensely bright per pixel in OIII and H-alpha, so they respond very well to a dual-band filter and do not need much time for the main shell. The faint outer halos most of them have are a different proposition and need hours. Keep subs short if the central region saturates.

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 Ghost of Jupiter with your DWARF II? Did the solid figure match?Anonymous, one tap. It is how the model gets calibrated.

Have an image of the Ghost of Jupiter 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 Ghost of Jupiter · All targets for the DWARF II