How long to image the Abell 39 with the DwarfLab DWARF II
From a Bortle 6 suburban sky, the DwarfLab DWARF II needs about 130+ h (30,570 subs of 15 s) for a solid image of the Abell 39. A quick look takes 32 h; a showpiece 510+ h. Under a Bortle 3 rural sky the solid figure drops to 61 h. 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 58 pixels across.
| Sky | Quick lookTarget obvious, still noisy | SolidClean enough to share | ShowpieceSmooth faint detail, print-worthy |
|---|---|---|---|
| Bortle 1Excellent dark site | 14 h3,249 subs | 54 h12,994 subs | 220+ h51,974 subs |
| Bortle 2Typical dark site | 14 h3,384 subs | 56 h13,534 subs | 230+ h54,133 subs |
| Bortle 3Rural | 15 h3,639 subs | 61 h14,555 subs | 240+ h58,218 subs |
| Bortle 4Rural / suburban transition | 18 h4,258 subs | 71 h17,029 subs | 280+ h68,114 subs |
| Bortle 5Suburban | 22 h5,238 subs | 87 h20,950 subs | 350+ h83,798 subs |
| Bortle 6Bright suburban | 32 h7,643 subs | 130+ h30,570 subs | 510+ h122,280 subs |
| Bortle 7Suburban / urban transition | 51 h12,226 subs | 200+ h48,902 subs | 820+ h195,605 subs |
| Bortle 8City | 81 h19,341 subs | 320+ h77,364 subs | 1290+ h309,453 subs |
| Bortle 9Inner city | 140+ h34,516 subs | 580+ h138,064 subs | 2300+ h552,255 subs |
Power and kit for this session
Allowing for slewing, focusing and rejected subs, that is about 170+ h of run time. That is more than one night: over 24 nights, about 6 h 54 min each. The DWARF II’s battery is rated at about 3 h, so each night 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.
Affiliate links: the retailer pays us a small commission and you pay the same price. These are search links to the named product, not endorsements of a particular listing; check the listing matches your model.
Everything that fits the DWARF II →
How it frames
The Abell 39 is 2.9′ across. The DWARF II frames 3.19° × 1.79° at 2.99″ per pixel, so it is small in the frame, about 58 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 Abell 39 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 Abell 39
A near-perfect faint sphere in Hercules. Very low surface brightness, an OIII target for dark skies and long dual-band stacks.
PN A66 39 · Planetary nebula in Hercules · magnitude 13.7 · 2.9′ · best in May, Jun, Jul. 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 Abell 39 from a DWARF II? Email it with your total time and sky to [email protected] and it goes here, credited.
Same target, other telescopes
- Abell 39 with the ZWO Seestar S50: 22 h from Bortle 6
- Abell 39 with the ZWO Seestar S50 Pro: 24 h from Bortle 6
- Abell 39 with the ZWO Seestar S30: 26 h from Bortle 6
- Abell 39 with the ZWO Seestar S30 Pro: 26 h from Bortle 6
- Abell 39 with the DwarfLab DWARF 3: 26 h from Bortle 6
- Abell 39 with the DwarfLab DWARF mini: 21 h from Bortle 6
- Abell 39 with the DwarfLab Draco: 17 h from Bortle 6
- Abell 39 with the Vaonis Vespera II: 37 h from Bortle 6
- Abell 39 with the Vaonis Vespera Pro: 83 h from Bortle 6
- Abell 39 with the Vaonis Vespera 3: 35 h from Bortle 6
- Abell 39 with the Vaonis Vespera Pro 2: 79 h from Bortle 6
- Abell 39 with the Unistellar eQuinox 2: 34 h from Bortle 6
- Abell 39 with the Unistellar Odyssey: 160+ h from Bortle 6
- Abell 39 with the Celestron Origin: 9 h 41 min from Bortle 6
- Abell 39 with the Celestron Origin Mark II: 13 h from Bortle 6
All telescopes for the Abell 39 · All targets for the DWARF II