 The sundial has two plaques on its base . The one on the left is a commemorative one discussing the benefactor and purpose of the sculpture . The benefactor of the sculpture was the B.F. Ferguson Monument fund , which has commissioned several works of art throughout Chicago . Many of the Ferguson fund 's commissioned works , such as the Fountain of the Great Lakes , are housed in and on the grounds of the Art Institute of Chicago or elsewhere in Grant Park . The purpose of the commission was to recognize the space exploration program . The plaque on the right is an equation of time table to correct for the time differences caused by the axial tilt of the Earth as well as its orbital eccentricity . As the plaque indicates with an additional correction , the equation of time table does not correct for daylight saving time . 
