The Virtual Observatory

The simplest Virtual Observatory query — 'give me every object within this radius of this position' — a standard that any catalogue service can answer, used constantly to find what is known around a point on the sky.

A Virtual Observatory protocol for finding and retrieving images of a region of sky from an archive, regardless of which telescope took them — the image counterpart of the cone search.

A Virtual Observatory protocol for finding and retrieving spectra of a target from an archive, bringing the spectroscopy of many instruments into a single uniform search.

A Virtual Observatory protocol for running database queries against an archive's catalogues over the web, returning the results as VOTables — the standard way to ask an archive a precise question about its tables.

The framework of standards, coordinated by the International Virtual Observatory Alliance, that lets the world's archives be searched and combined as if they were one — so an astronomer can query every telescope's data at once. TAP, Cone Search, VOEvent, and VOTable are among its standards.