Physics and Astronomy: Constants, Tables & Data

"The NASA Exoplanet Archive collects and serves public data to support the search for and characterization of extra-solar planets (exoplanets) and their host stars. The data include published light curves, images, spectra and parameters, and time-series data from surveys that aim to discover transiting exoplanets."

NPL is the UK's National Measurement Institute, developing and maintaining the national primary measurement standards.