How long to image the M70 with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 54 min (217 subs of 15 s) for a solid image of the M70. A quick look takes 14 min; a showpiece 3 h 37 min. Under a Bortle 3 rural sky the solid figure drops to 31 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 7% 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 | 7 min30 subs | 29 min117 subs | 1 h 56 min466 subs |
| Bortle 2Typical dark site | 7 min30 subs | 30 min120 subs | 2 h479 subs |
| Bortle 3Rural | 8 min32 subs | 31 min126 subs | 2 h 05 min502 subs |
| Bortle 4Rural / suburban transition | 9 min35 subs | 35 min140 subs | 2 h 19 min558 subs |
| Bortle 5Suburban | 10 min41 subs | 40 min162 subs | 2 h 42 min648 subs |
| Bortle 6Bright suburban | 14 min55 subs | 54 min217 subs | 3 h 37 min867 subs |
| Bortle 7Suburban / urban transition | 20 min81 subs | 1 h 20 min322 subs | 5 h 21 min1,285 subs |
| Bortle 8City | 30 min121 subs | 2 h 01 min484 subs | 8 h 03 min1,934 subs |
| Bortle 9Inner city | 52 min208 subs | 3 h 27 min830 subs | 14 h3,319 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 1 h 10 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.)
- 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 M70 is 8′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 7% of the frame’s short side.
About the M70
M69's near twin two degrees east, a compact globular in the same low field.
NGC 6681 · Globular cluster in Sagittarius · magnitude 7.9 · 8′ · best in Jun, Jul, Aug. 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 M70 from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M70 with the ZWO Seestar S50: 16 min from Bortle 6
- M70 with the ZWO Seestar S50 Pro: 18 min from Bortle 6
- M70 with the ZWO Seestar S30: 17 min from Bortle 6
- M70 with the ZWO Seestar S30 Pro: 19 min from Bortle 6
- M70 with the DwarfLab DWARF 3: 24 min from Bortle 6
- M70 with the DwarfLab DWARF mini: 16 min from Bortle 6
- M70 with the DwarfLab Draco: 15 min from Bortle 6
- M70 with the Vaonis Vespera II: 16 min from Bortle 6
- M70 with the Vaonis Vespera Pro: 36 min from Bortle 6
- M70 with the Vaonis Vespera 3: 16 min from Bortle 6
- M70 with the Vaonis Vespera Pro 2: 35 min from Bortle 6
- M70 with the Unistellar eQuinox 2: 14 min from Bortle 6
- M70 with the Unistellar Odyssey: 1 h 03 min from Bortle 6
- M70 with the Celestron Origin: 5 min from Bortle 6
- M70 with the Celestron Origin Mark II: 6 min from Bortle 6