Method Categories

Measuring the precise positions and motions of the stars — parallax, proper motion, and the space astrometry that has mapped over a billion stars. The foundation on which distances across the galaxy are built.

Measuring how bright things are and resolving their fine detail — the magnitude system, precision photometry, and the interferometry and adaptive optics that sharpen the view.

Splitting light into its spectrum to read the composition, temperature, motion, and magnetic fields of distant objects — and classifying stars by what their spectra reveal.

How astronomers measure distances across the universe — a ladder from parallax to standard candles to redshift, each rung calibrating the next, reaching from nearby stars to the edge of the observable universe.

The techniques that find and weigh planets around other stars — from the tiny dimming of a transit to the wobble of radial velocity — most of them modelled already in the exoplanet encyclopedia.

Watching how things change with time — the oscillations that let us sound the interiors of the Sun and stars, the occultations that reveal sizes, and the study of the variable and transient sky.

Astronomy beyond light — the bending of light by gravity, the direct detection of gravitational waves and cosmic neutrinos, and the combined multi-messenger view of the most violent events.

How raw measurements become knowledge — deriving the properties of stars and galaxies, weighing black holes, mapping dark matter through rotation curves, and the calibration, error analysis, and honest uncertainty that make a measurement science.