The Center for Astrophysics (CfA) is offering a viewing of Mars at its Oak Ridge Observatory in Harvard, Mass., this Sunday (Aug. 24). For one night only, a drawing will give 40 lucky sky-watchers – weather permitting – a chance to view Mars through the 61-inch-diameter Wyeth reflector (the largest optical telescope east of the Mississippi). A 16-inch reflector and other telescopes will be available to all other guests. CfA will offer tours of the observatory from 7:30 to 8:30 p.m., followed by public viewing from 8:30 to 10 p.m. The rain date is Aug. 25. The Oak Ridge Observatory is at 40 Pinnacle Road.