What does the SDSS logo represent?
The Sloan Digital Sky Survey’s goal is to image half of the northern celestial hemisphere (one quarter of the total sky), as well as a smaller portion of the southern sky. The portion of the universe that the survey will observe is represented by our vaguely parachute-shaped logo. We are at the center of the logo, at the vertex of the parachute strings. The elliptical background evokes the shape of a galaxy, the celestial object of greatest interest to the Sloan Survey. Because the total solid angle (area) of the survey will be 10,000 square degrees, or pi steradians, the logo is sometimes jokingly referred to as “pi on the sky”.
