National Geographic : 1952 Feb
252 National Geographic Photographer J. Baylor lRoberts A Celestial Wanderer Is Caught Approaching the Earth's Orbit The author and Dr. Rudolph Minkowski last August 31 detected a newcomer on a Sky Survey plate. Their discovery proved to be an asteroid, one of seven known to pass near the earth's orbit. It was named 1951RA for the year and order of its discovery. Two circles (above) show 1951RA's movement, about 1/4 degrees, in 24 hours. Motion during a 10-minute exposure gives the object a hyphen-shaped appearance. A star map (below) traces the visitor's path from August 31 (figure 1) to September 21 and 22 (figures 2 and 3). The chart is repro duced from the Skalnate Pleso, published by the Sky Publishing Corporation, Cambridge, Massachusetts.