Tools
NASA/IPAC Extragalactic Database (NED)
SAO/NASA Astrophysics Data System (ADS)
arXiv.org astro-ph (preprints)
AstroBetter
Useful Equations for Radio Astronomy (Tobias Westmeier)
Coyote's Guide to IDL Programming
NED Coordinate Transformation and Extinction Calculator
Essential Radio Astronomy Course
VizieR Service
Web Interface for Skycalendar and SkyCalc (Brian Casey)
American Astronomical Society