How long to image the Jellyfish Nebula with the DwarfLab DWARF II

From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 23 h (5,479 subs of 15 s) for a solid image of the Jellyfish Nebula. A quick look takes 5 h 42 min; a showpiece 91 h. Under a Bortle 3 rural sky the solid figure drops to 11 h. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 46% of the frame’s short side.

Jellyfish Nebula with the DwarfLab DWARF II: 15 s subs.
SkyQuick lookTarget obvious, still noisySolidClean enough to shareShowpieceSmooth faint detail, print-worthy
Bortle 1Excellent dark site2 h 28 min593 subs9 h 52 min2,369 subs39 h9,474 subs
Bortle 2Typical dark site2 h 34 min616 subs10 h2,464 subs41 h9,856 subs
Bortle 3Rural2 h 45 min662 subs11 h2,645 subs44 h10,579 subs
Bortle 4Rural / suburban transition3 h 13 min771 subs13 h3,083 subs51 h12,330 subs
Bortle 5Suburban3 h 56 min945 subs16 h3,777 subs63 h15,105 subs
Bortle 6Bright suburban5 h 42 min1,370 subs23 h5,479 subs91 h21,914 subs
Bortle 7Suburban / urban transition9 h 05 min2,181 subs36 h8,722 subs150+ h34,888 subs
Bortle 8City14 h3,440 subs57 h13,758 subs230+ h55,031 subs
Bortle 9Inner city26 h6,125 subs100+ h24,498 subs410+ h97,992 subs

Adjust in the calculator

Power and kit for this session

Allowing for slewing, focusing and rejected subs, that is about 30 h of run time. That is more than one night: over 5 nights, about 5 h 56 min each. The DWARF II’s battery is rated at about 3 h, less near freezing, so each night needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time, and 30% off the battery for a January night.)

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How it frames

The Jellyfish Nebula is 50′ × 40′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 46% of the frame’s short side.

Filters

The Jellyfish Nebula 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 Jellyfish Nebula

A supernova remnant beside Propus in Gemini, with a bright rim like a jellyfish bell. Faint; dual-band and hours.

IC 443, Sh2-248 · Supernova remnant in Gemini · magnitude 12.0 · 50′ × 40′ · best in Dec, Jan, Feb. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.

Supernova remnants are emission-line objects, strong in both hydrogen-alpha and OIII, and their filaments are thin, so pixel scale matters as much as aperture. A dual-band filter is essential from any lit sky and still helps under a dark one. These are long-integration targets; plan on several sessions and stack across nights.

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

Have an image of the Jellyfish Nebula 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 Jellyfish Nebula · All targets for the DWARF II