How long to image the M18 with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 14 min (55 subs of 15 s) for a solid image of the M18. A quick look takes 3 min; a showpiece 55 min. Under a Bortle 3 rural sky the solid figure drops to 9 min. At Bortle 6 the limit is a mix of skyglow and read noise. In this scope's field it fills 8% 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 | 3 min10 subs | 9 min35 subs | 34 min137 subs |
| Bortle 2Typical dark site | 3 min10 subs | 9 min35 subs | 35 min140 subs |
| Bortle 3Rural | 3 min10 subs | 9 min37 subs | 36 min145 subs |
| Bortle 4Rural / suburban transition | 3 min10 subs | 10 min39 subs | 39 min156 subs |
| Bortle 5Suburban | 3 min11 subs | 11 min44 subs | 44 min175 subs |
| Bortle 6Bright suburban | 3 min14 subs | 14 min55 subs | 55 min220 subs |
| Bortle 7Suburban / urban transition | 5 min20 subs | 19 min77 subs | 1 h 16 min306 subs |
| Bortle 8City | 7 min28 subs | 27 min110 subs | 1 h 50 min440 subs |
| Bortle 9Inner city | 11 min46 subs | 45 min182 subs | 3 h 01 min725 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 18 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 M18 is 9′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it fills 8% of the frame’s short side.
About the M18
A small, sparse open cluster just south of the Omega Nebula. Usually caught in the same frame.
NGC 6613 · Open cluster in Sagittarius · magnitude 6.9 · 9′ · best in Jun, Jul, Aug. Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
Open clusters are the easiest targets in the sky. The stars are bright, so the aim is colour and tight stars rather than depth: short subs, no filter, and stop before the bright members saturate. The nominal time here gets you clean star colour; more integration only adds background stars.
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 M18 from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M18 with the ZWO Seestar S50: 5 min from Bortle 6
- M18 with the ZWO Seestar S50 Pro: 5 min from Bortle 6
- M18 with the ZWO Seestar S30: 5 min from Bortle 6
- M18 with the ZWO Seestar S30 Pro: 5 min from Bortle 6
- M18 with the DwarfLab DWARF 3: 8 min from Bortle 6
- M18 with the DwarfLab DWARF mini: 8 min from Bortle 6
- M18 with the DwarfLab Draco: 15 min from Bortle 6
- M18 with the Vaonis Vespera II: 5 min from Bortle 6
- M18 with the Vaonis Vespera Pro: 9 min from Bortle 6
- M18 with the Vaonis Vespera 3: 5 min from Bortle 6
- M18 with the Vaonis Vespera Pro 2: 9 min from Bortle 6
- M18 with the Unistellar eQuinox 2: 3 min from Bortle 6
- M18 with the Unistellar Odyssey: 15 min from Bortle 6
- M18 with the Celestron Origin: 5 min from Bortle 6
- M18 with the Celestron Origin Mark II: 5 min from Bortle 6