... Each day we feature a different image or photograph of our fascinating universe, along with a brief explanation written by a professional astronomer. January 18, 1996 . MyCn18: An Hourglass Nebula . Credit: R. Sahai and J. Trauger ( JPL ), WFPC2 Science Team , NASA , . Explanation: The sands of time are running out for the central star of this hourglass-shaped planetary nebula . ... About APOD | ... NASA Technical Rep.: ... A service of: LHEA at NASA / GSFC . ...