Abstract
In the l990's, the confluence of personal computing and digital data acquisition made it possible to produce realistic simulations of astronomical instrumentation for classroom use. Since its inception in 1992, Project CLEA
(Contemporary Laboratory Experiences in Astronomy) has taken advantage of these developments to introduce a series of PC-based exercises that simulate a wide variety of astronomical research techniques including spectroscopy,
CCD imaging, and radio astronomy of pulsars. Project CLEA materials have been widely adopted by astronomy educators because they make it possible to involve students in hands-on investigations that would otherwise be difficult
because of time, weather, and financial constraints on real telescopes.
In recent years, Project CLEA software has been developed to take advantage of vastly increased computer power and data base resources as well as the Internet. It is now possible to offer access to tens of millions of objects covering the entire sky, using a variety of simulated observing instruments that span a wide range of wavelengths. As research astronomers plan "virtual observatories" - huge research databases fed by automated
survey instruments - the experience provided by well-designed instructional simulations gains additional importance. In the future, it may be only through simulations that most students develop an intuitive understanding of the observational basis of astronomy.
