Participate in the International Year of Astronomy by making a visit to the observatory on top of Crow Hall. It is open to the Washington University community on reasonably clear Monday through Thursday evenings from when the sky is dark — now about 7 p.m. — to 10 p.m. during the fall semester. Admission is free. The observatory’s telescope, which was donated to WUSTL in 1859, is the oldest instrument in the Department of Physics in Arts & Sciences. The lenses for the 6-inch refractor telescope were made by Henry Fitz & Co. and refigured in 1882 by Alvan Clark & Sons, both notable 19th-century American telescope makers. For more information about viewing the night sky through the observatory’s telescope, visit physics.wustl.edu/Overview/Docs/Observatory.php. Visitors should call 935-6278 during viewing hours to be sure that the observatory is open.