How long to image the M72 with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 4 h 02 min (967 subs of 15 s) for a solid image of the M72. A quick look takes 1 h; a showpiece 16 h. Under a Bortle 3 rural sky the solid figure drops to 2 h 07 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 6% of the frame’s short side.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 29 min117 subs | 1 h 56 min465 subs | 7 h 45 min1,860 subs |
| Bortle 2Typical dark site | 30 min121 subs | 2 h481 subs | 8 h1,922 subs |
| Bortle 3Rural | 32 min128 subs | 2 h 07 min510 subs | 8 h 29 min2,038 subs |
| Bortle 4Rural / suburban transition | 36 min146 subs | 2 h 25 min581 subs | 9 h 40 min2,321 subs |
| Bortle 5Suburban | 43 min173 subs | 2 h 53 min692 subs | 12 h2,768 subs |
| Bortle 6Bright suburban | 1 h242 subs | 4 h 02 min967 subs | 16 h3,866 subs |
| Bortle 7Suburban / urban transition | 1 h 33 min373 subs | 6 h 12 min1,490 subs | 25 h5,959 subs |
| Bortle 8City | 2 h 24 min576 subs | 9 h 35 min2,302 subs | 38 h9,207 subs |
| Bortle 9Inner city | 4 h 12 min1,009 subs | 17 h4,034 subs | 67 h16,136 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 5 h 14 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 M72 is 6′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 6% of the frame’s short side.
About the M72
A faint, distant globular in Aquarius. Among the harder Messier globulars.
NGC 6981 · Globular cluster in Aquarius · magnitude 9.3 · 6′ · best in Jul, Aug, Sep. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Globular clusters are point sources packed tight, so they come quickly: the core resolves into stars within a handful of minutes on any smart scope. More time deepens the halo and pulls in the faint outer members. Use short subs so the core does not saturate into a white blob, and no filter.
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 M72 from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M72 with the ZWO Seestar S50: 1 h 11 min from Bortle 6
- M72 with the ZWO Seestar S50 Pro: 1 h 18 min from Bortle 6
- M72 with the ZWO Seestar S30: 1 h 15 min from Bortle 6
- M72 with the ZWO Seestar S30 Pro: 1 h 23 min from Bortle 6
- M72 with the DwarfLab DWARF 3: 1 h 44 min from Bortle 6
- M72 with the DwarfLab DWARF mini: 1 h 11 min from Bortle 6
- M72 with the DwarfLab Draco: 59 min from Bortle 6
- M72 with the Vaonis Vespera II: 1 h 11 min from Bortle 6
- M72 with the Vaonis Vespera Pro: 2 h 39 min from Bortle 6
- M72 with the Vaonis Vespera 3: 1 h 08 min from Bortle 6
- M72 with the Vaonis Vespera Pro 2: 2 h 32 min from Bortle 6
- M72 with the Unistellar eQuinox 2: 1 h 04 min from Bortle 6
- M72 with the Unistellar Odyssey: 4 h 51 min from Bortle 6
- M72 with the Celestron Origin: 19 min from Bortle 6
- M72 with the Celestron Origin Mark II: 26 min from Bortle 6