|IC 4997: Planetary Nebula (Sagitta) RA: 20h 20.2m / DEC: +16° 43'.9|
Instrument: 18-inch Obsession
IC 4997 is bright--11th magnitude--and the field is easy enough to locate--0.0 mag. HD 355464 is 1' away. But this planetary nebula is only 2" in size and that makes it a legitimate deep-sky challenge. The sketch at left presents a 272X view in the 18-inch Obsession. The centered, bright star is HD 355464. A pair of 13th magnitude stars simmer nearby, just arc seconds to the southwest. The relatively bright "star" 1' to the northeast is IC 4997. This stellar planetary is the one object in the field that doesn't dim significantly when an OIII filter is slid into position. The other giveaway as to IC 4997's true nature, is its slightly fuzzy appearance at high power. It looks like any other 11th magnitude star at low power. But bump up the magnification, and this planetary nebula dons a fuzzy edge.
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Revised: July 7, 2005 [WDF]