He teaches astronomy as well as physics courses in traditional and online formats. Greg has worked in the aerospace sector, where he specialized in star simulation and space optics. An early job was with Perkin-Elmer on the Hubble Space Telescope. Greg performed measurements for vibration testing of the secondary mirror, and helped with design and fabrication of the star simulator to test the Optical Control system and Fine Guidance System of HST. Later jobs with Bendix Aerospace involved star simulation for satellite navigation systems. Greg has written test banks for astronomy and physics texts and is currently involved in a project for teacher certification exams.