Optical Interferometry
IDL Routines for manipulating the OI-DATA FITS format
Bad Calibrator Database
OI-DATA exchange format webpage (John Young)
Optical Long Baseline Interferometer News

Astronomy (in general)
Astronomy Picture of the Day

Size comparison (Earth to VY CMa)

Physical Data
Periodic Table of the Elements (american

Research Centers
Harvard- Smithsonian Center for Astrophysics