How long to image the M103 with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 19 min (75 subs of 15 s) for a solid image of the M103. A quick look takes 5 min; a showpiece 1 h 14 min. Under a Bortle 3 rural sky the solid figure drops to 12 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 | 3 min12 subs | 12 min47 subs | 46 min185 subs |
| Bortle 2Typical dark site | 3 min12 subs | 12 min48 subs | 47 min189 subs |
| Bortle 3Rural | 3 min13 subs | 12 min49 subs | 49 min195 subs |
| Bortle 4Rural / suburban transition | 3 min14 subs | 13 min53 subs | 53 min211 subs |
| Bortle 5Suburban | 4 min15 subs | 15 min59 subs | 59 min236 subs |
| Bortle 6Bright suburban | 5 min19 subs | 19 min75 subs | 1 h 14 min297 subs |
| Bortle 7Suburban / urban transition | 6 min26 subs | 26 min104 subs | 1 h 43 min413 subs |
| Bortle 8City | 9 min38 subs | 37 min149 subs | 2 h 28 min593 subs |
| Bortle 9Inner city | 15 min62 subs | 1 h 01 min245 subs | 4 h 04 min978 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 24 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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How it frames
The M103 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 M103
A small, fan-shaped open cluster in Cassiopeia, the last object in Messier's own list.
NGC 581 · Open cluster in Cassiopeia · magnitude 7.4 · 6′ · best in Sep, Oct, Nov. 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 M103 from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- M103 with the ZWO Seestar S50: 6 min from Bortle 6
- M103 with the ZWO Seestar S50 Pro: 6 min from Bortle 6
- M103 with the ZWO Seestar S30: 6 min from Bortle 6
- M103 with the ZWO Seestar S30 Pro: 7 min from Bortle 6
- M103 with the DwarfLab DWARF 3: 9 min from Bortle 6
- M103 with the DwarfLab DWARF mini: 8 min from Bortle 6
- M103 with the DwarfLab Draco: 15 min from Bortle 6
- M103 with the Vaonis Vespera II: 6 min from Bortle 6
- M103 with the Vaonis Vespera Pro: 13 min from Bortle 6
- M103 with the Vaonis Vespera 3: 6 min from Bortle 6
- M103 with the Vaonis Vespera Pro 2: 12 min from Bortle 6
- M103 with the Unistellar eQuinox 2: 5 min from Bortle 6
- M103 with the Unistellar Odyssey: 20 min from Bortle 6
- M103 with the Celestron Origin: 5 min from Bortle 6
- M103 with the Celestron Origin Mark II: 5 min from Bortle 6