AAVSO - American Association of Variable Star Observers
Astronomical Society of Southern Australia - Variable Star Group
BAA Variable Star Section
BAV - Bundesdeutsche Arbeitsgemeinschaft fur Veranderliche Sterne
CBA - Center for Backyard Astrophysics
IAPPP
IAU Commission 27: Variable Stars
VSNET - Variable Star Network
Dan Bruton's Eclipsing Binary Page
McMaster Cepheid Photometry and Radial Velocity Archive
David Dunlap Observatory Database of Galactic Classical Cepheids
Siobahn Morgan's Archive of Fourier Coefficients
Be Star Newsletter
delta Scuti Star Newsletter
General Catalog of Variable Stars - form interface
Information Bulletin on Variable Stars (IBVS)
AGAPE
ASAS - All-Sky Automated Survey
EROS Project
HCO - Harvard College Observatory Archival Photometry of the LMC and SMC
MACHO Project
MOA
OGLE Project
PLANET Project
SDSS - Sloan Digital Sky Survey
STARE - STellar Astrophysics and Results on Exoplanets
TASS - The Amateur Sky Survey
Eclipsing Binary simulation [JAVA]
Calendar Date to Julian Date calculator [Javascript]
CCDEZMAG
EzPhot
Julian Date to Calendar Date calculator [Javascript]
HEASARC Date Conversion calculator
Muni-DOS (Programs for CCD Photometry on a PC)
Database of RR Lyrae Observations
Karl Dubost's "Variable Stars Database Tools" Page
Chris Lloyd's "Random Variable" Page
Brian Skiff's "Precise Positions for Landolt Standard Stars"
Notes for Landolt Standards