| Planetary
Nebula
aka PNG 047.0+42.4, PK 047+42.1, Abell 39, ARO 180 RA: 16h27m32.6s Dec: +27°54'29" (Hercules) Integrated Visual Magnitude: 13.7 Angular Diameter: 2.9' Mean Surface Brightness: 24.6 Mag/arc-sec² Distance 4400 ly Minimum requirements to detect: 8-inch under dark skies |
Abell 39 is a relatively large and diffuse planetary nebula. A 15.7 magnitude central star lies within.
The nebula will require very dark skies to see without a filter, particularly with telescopes smaller than 16 inches. It appears as a round hazy patch that is very faint. This one is a challenge for an eight-inch scope where it will appear as a round patch, large and faint. Even with an OIII or UHC filter it may only be glimpsed with averted vision.
Sixteen-inch or larger scopes will reveal a sharp edge and a slightly darker central region provided an OIII or UHC filter is employed.
The view in a 12-inch
at 51x.
In my 18-inch without a filter it was a very challenging object, appearing as a very slight round haze with averted vision. I had to observe this one on different nights and spend a great deal of time to convince myself that I really did see it. The OIII filter really helps bring it out.
The above color image was created by combining red and blue second-generation DSS images. Note the apparent faint distant galaxies within the bounds of the nebula!
| Millennium
Star Atlas Vol III Chart 1181
Sky Atlas 2000 Chart 8 Uranometria 2000 Vol I Chart 156 Herald-Bobroff Astroatlas B-05 C-21 |
