How long to image the Little Dumbbell with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 2 h 32 min (608 subs of 15 s) for a solid image of the Little Dumbbell. A quick look takes 38 min; a showpiece 10 h. Under a Bortle 3 rural sky the solid figure drops to 1 h 22 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 54 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 19 min76 subs | 1 h 16 min303 subs | 5 h 03 min1,211 subs |
| Bortle 2Typical dark site | 19 min78 subs | 1 h 18 min312 subs | 5 h 12 min1,248 subs |
| Bortle 3Rural | 21 min83 subs | 1 h 22 min330 subs | 5 h 30 min1,319 subs |
| Bortle 4Rural / suburban transition | 23 min94 subs | 1 h 33 min373 subs | 6 h 13 min1,491 subs |
| Bortle 5Suburban | 28 min111 subs | 1 h 50 min441 subs | 7 h 21 min1,764 subs |
| Bortle 6Bright suburban | 38 min152 subs | 2 h 32 min608 subs | 10 h2,432 subs |
| Bortle 7Suburban / urban transition | 58 min232 subs | 3 h 52 min927 subs | 15 h3,707 subs |
| Bortle 8City | 1 h 29 min356 subs | 5 h 55 min1,422 subs | 24 h5,685 subs |
| Bortle 9Inner city | 2 h 35 min619 subs | 10 h2,476 subs | 41 h9,904 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 3 h 18 min of run time. The DWARF II’s battery is rated at about 3 h, so the session needs an external power bank. (Bortle 6, solid image; we allow 30% over the integration time.)
- USB-C PD power bank 10000mAh 18W18 W PD input; runs while charging.
- red LED head torchRed light keeps your night vision; white light costs you twenty minutes of dark adaptation every time.
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Everything that fits the DWARF II →
How it frames
The Little Dumbbell is 2.7′ × 1.8′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it is small in the frame, about 54 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 Little Dumbbell 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 Little Dumbbell
A small, bright-per-pixel planetary in Perseus. Dual-band makes the two lobes and the faint wings much easier.
M76, NGC 650 · Planetary nebula in Perseus · magnitude 10.1 · 2.7′ × 1.8′ · best in Sep, Oct, Nov. 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.
Have an image of the Little Dumbbell from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Little Dumbbell with the ZWO Seestar S50: 33 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S50 Pro: 36 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S30: 37 min from Bortle 6
- Little Dumbbell with the ZWO Seestar S30 Pro: 39 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF 3: 43 min from Bortle 6
- Little Dumbbell with the DwarfLab DWARF mini: 32 min from Bortle 6
- Little Dumbbell with the DwarfLab Draco: 26 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera II: 45 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera Pro: 1 h 41 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera 3: 43 min from Bortle 6
- Little Dumbbell with the Vaonis Vespera Pro 2: 1 h 36 min from Bortle 6
- Little Dumbbell with the Unistellar eQuinox 2: 40 min from Bortle 6
- Little Dumbbell with the Unistellar Odyssey: 3 h 01 min from Bortle 6
- Little Dumbbell with the Celestron Origin: 12 min from Bortle 6
- Little Dumbbell with the Celestron Origin Mark II: 17 min from Bortle 6
All telescopes for the Little Dumbbell · All targets for the DWARF II