Fiske Planetarium and Sommers-Bausch Observatory at the University of Colorado at Â鶹¹ÙÍø will hold Astronomy Day activities including rocket launches, sunspot viewing and demonstrations of planetarium and observatory equipment on Saturday, April 19, from noon to 10 p.m. "We are actually celebrating Astronomy Day a little early this year," said Sanlyn Buxner, an education specialist for Fiske Planetarium. The national day of celebration will be May 10, which is after CU-Â鶹¹ÙÍø commencement, she said. "We wanted to do our celebration before students leave for the summer."