Planetary Nebulae Images 7


NGC2438, in Puppis, is a ring nebula approximately 65" in diameter (just over 1 arc-minute) and blazes forth at almost mag 10. The central star is difficult at mag 17.	NGC6772, a quite difficult mag 14 PNe in the constellation Aquila is more oval than round and thus its size is quoted as 75" x 50". When viewed through an eyepiece, it appears uneven in brightness and in a rich star field.


NGC6804, an irregularly round PNe also in Aquila, is fairly bright at around mag 11. The central star, between mag 13 and 14, can be viewed with averted vision	Abell78, a larger and fainter PNe in Cygnus. The size (113"x 88") and published magnitude (16) surely indicate a difficult object! The outer halo is mainly hydrogen while the inner is mainly helium.	NGC2818, also designated as planetary Hubble2, is located at a declination of -36 in the con- stellation Pyxis. It is physically associated with a star cluster, rare for planetary nebulae.


NGC6445 in Sagittarius, is about 38" x 29" in size and is mistakenly identified in some literature as "The Little Gem". But this name is identified with NGC6818, also found in Sagittarius. NGC6445 is moderately bright and forms a striking pair (in a lower power field) with the near- by globular cluster NGC6440 (SSW).	NGC6337, a smaller, fainter ring nebula in Scorpius is best viewed with averted vision and high power. The size is about 50" and its calculated surface brightness is 11.6 (visual mag. of about 12). The central star is a dim mag. 15.