NGC/IC Project Restoration Effort

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NGC3918

 

Basic Information


Location and Magnitude


Right Ascension: 11:50:17.8
Declination: -57:10:55
Constellation: CEN
Visual Magnitude: 8.1

Historic Information


Discoverer: Herschel J.
Year of discovery: 1834
Discovery aperture: 18.3

Observational


Summary description: planetary, !, S, R, blue, = * 7m, d=1s.5
Sub-type: PN

Steve's Notes

===== NGC 3918 24" (4/11/08 - Magellan Observatory, Australia): at 200x the "Blue Planetary" has an even, extremely high surface brightness disc of 15" and a saturated, vivid blue color. The edge is crisply defined and the disc has a uniform surface brightness. At 350x, the planetary is oval or irregular, perhaps 18"x15". There was no sign of the central star, though I didn't try higher powers. 18" (7/10/05 - Magellan Observatory, Australia): at 76x appears as a bright, beautiful blue cosmic egg floating in a rich star field, ~15" diameter. Extremely high surface brightness and with a sharply defined edge to the uniformly lit disc. At 228x, appears to be set in the middle of an absorption hole in the Milky Way as there are very few faint stars in a 4'-5' circular region surrounding the planetary. Outside this hole, the Milky Way background is very evident and fairly bright. 13.1" (2/20/04 - Costa Rica): at 195x, this 8th magnitude planetary appears as a beautiful 10"-12" blue disc with a very crisp edge. No central star was glimpsed or other structural details at this magnification though the surface brightness is unusually high. Situated in a rich star field but set near the middle of a oval 12'-13' ring of mag 11 and 12 stars which are near the periphery of the 17' field at 195x! Located 8.4' SSW of mag 8.1 HD 102817 and 19' SW of mag 5.6 HD 103101. The open cluster NGC 3960 lies 90' N. 18" (7/8/02 - Magellan Observatory, Australia): at 171x, the "Blue Planetary" appears as a bright, round disc, ~15" diameter with a vivid blue color (V = 8.2). The surface brightness is very high and the edge of the halo is crisply defined, but no structural details or central star were noted. Good response to UHC filter, although it was unnecessary for a good view. The Milky Way is quite rich here in faint stars but the planetary seems to be set a darker, circular hole without the faint background glow - a contrast affect with the PN?