Parallax method The apparent movement of close stars against the background of stars
When d = 1 parsec ; p = one second
However: beyond 300 parsecs the angle is too small to measure and so can't measure the distance to most stars
Brightness method Further away stars appear dimmer but this assumes all stars have the same luminosity (temperature and size)
Cepheid variable stars are stars which vary in brightness those with higher luminosity have longer periods. They can be used in the brightness method by comparing stars with the same apparent brightness to the luminosity.
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