arXiv (Astrophysics, Condensed Matter, General Relativity and Quantum Cosmology, High Energy Physics, Mathematical Physics, Nonlinear Sciences, Nuclear Experiment, Nuclear Theory, Physics, Quantum Physics)
ADS (SAO/NASA Astrophysics Data System)
NED (NASA Extragalactic Database)
ESO (European Southern Observatory) Archive
DSS Online Digitized Sky Survey
MAST (Mikulski Archive for Space Telescopes)
IRSA (Infrared Science Archive)
2MASS (Two Micron All Sky Survey, also via IRSA
HSA (Herschel Science Archive)
HEASARC (High Energy Astrophysics Archive Research Center)
LAMBDA (Legacy Archive for Microwave Background Data Analysis)
NSSDC (National Space Science Data Center)
GAVO (German Astrophysical Virtual Observatory)
EURO-VO (European Virtual Observatory)
VAO (Virtual Astronomical Observatory)
IVOA (International Virtual Observatory Alliance)