Abell 39
PN A66 39 · Planetary nebula in Hercules
- Magnitude
- 13.7
- Size
- 2.9′
- Effective surface brightness
- 23.5 mag/arcsec²
- Best months
- May, Jun, Jul
- Declination
- +28°
- Filter
- Dual-band recommended
A near-perfect faint sphere in Hercules. Very low surface brightness, an OIII target for dark skies and long dual-band stacks.
Reachable from mid-northern latitudes (UK, northern US, central Europe) and from the south.
How long with each smart telescope
| Telescope | In frame | Bortle 3 (rural) | Bortle 5 (suburban) | Bortle 7 (urban edge) |
|---|---|---|---|---|
| ZWO Seestar S5010 s subs, dual-band | 7% | 14 h5,179 subs | 17 h6,236 subs | 30 h10,857 subs |
| ZWO Seestar S50 Pro10 s subs, dual-band | 4% | 17 h5,951 subs | 20 h7,095 subs | 34 h12,092 subs |
| ZWO Seestar S3010 s subs, dual-band | 44 px | 18 h6,632 subs | 21 h7,689 subs | 34 h12,310 subs |
| ZWO Seestar S30 Pro10 s subs, dual-band | 47 px | 18 h6,514 subs | 21 h7,716 subs | 36 h12,974 subs |
| DwarfLab DWARF 315 s subs, dual-band | 3% | 15 h3,564 subs | 19 h4,653 subs | 39 h9,411 subs |
| DwarfLab DWARF mini15 s subs, dual-band | 44 px | 14 h3,365 subs | 17 h4,070 subs | 30 h7,150 subs |
| DwarfLab Draco30 s subs, dual-band | 4% | 11 h1,317 subs | 13 h1,611 subs | 24 h2,895 subs |
| DwarfLab DWARF II15 s subs | 58 px | 61 h14,555 subs | 87 h20,950 subs | 200+ h48,902 subs |
| Vaonis Vespera II10 s subs | 3% | 13 h4,588 subs | 22 h8,041 subs | 64 h23,135 subs |
| Vaonis Vespera Pro10 s subs | 3% | 32 h11,572 subs | 52 h18,832 subs | 140+ h50,567 subs |
| Vaonis Vespera 310 s subs | 3% | 12 h4,333 subs | 21 h7,649 subs | 62 h22,145 subs |
| Vaonis Vespera Pro 210 s subs | 3% | 30 h10,885 subs | 50 h17,858 subs | 130+ h48,336 subs |
| Unistellar eQuinox 24 s subs | 8% | 19 h17,165 subs | 25 h22,546 subs | 51 h46,065 subs |
| Unistellar Odyssey4 s subs | 9% | 100+ h94,040 subs | 130+ h113,618 subs | 220+ h199,189 subs |
| Celestron Origin10 s subs | 6% | 2 h 52 min1,032 subs | 5 h 35 min2,012 subs | 17 h6,294 subs |
| Celestron Origin Mark II10 s subs | 6% | 3 h 25 min1,233 subs | 7 h 20 min2,643 subs | 24 h8,809 subs |
Imaging the planetary nebula
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.
Per-telescope pages
- How long to image the Abell 39 with the ZWO Seestar S50
- How long to image the Abell 39 with the ZWO Seestar S50 Pro
- How long to image the Abell 39 with the ZWO Seestar S30
- How long to image the Abell 39 with the ZWO Seestar S30 Pro
- How long to image the Abell 39 with the DwarfLab DWARF 3
- How long to image the Abell 39 with the DwarfLab DWARF mini
- How long to image the Abell 39 with the DwarfLab Draco
- How long to image the Abell 39 with the DwarfLab DWARF II
- How long to image the Abell 39 with the Vaonis Vespera II
- How long to image the Abell 39 with the Vaonis Vespera Pro
- How long to image the Abell 39 with the Vaonis Vespera 3
- How long to image the Abell 39 with the Vaonis Vespera Pro 2
- How long to image the Abell 39 with the Unistellar eQuinox 2
- How long to image the Abell 39 with the Unistellar Odyssey
- How long to image the Abell 39 with the Celestron Origin
- How long to image the Abell 39 with the Celestron Origin Mark II