... Interstellar Molecular Clouds . E. Samuel Palmer - Harvard Smithsonian Center for Astrophysics . ... This telescope can see and interpret interstellar CO, a molecular mass tracer for what it can’t see, that is, molecular hydrogen which constitutes most of the mass in giant molecular clouds. ... Covering all the bases, he is also a fellow amateur astronomer, observing the handful of stars occasionally visible from his home in Arlington. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...