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Sprinkles of starlight
Parallax/Parsec
A star's parallax is the angle it appears to move against the background of more-distant objects as Earth moves from one side of the Sun to the other. Astronomers use that angle to measure the star's distance. The technique provides highly accurate distances out to a few hundred light-years, and less-accurate ones out to thousands or tens of thousands of light-years. Astronomers generally express distances to stars and galaxies in parsecs, which is short for parallax-seconds, or the parallax in seconds of arc. One parsec equals 3.26 light-years. When describing a star's absolute magnitude, or its true brightness, astronomers use a standard distance of 10 parsecs, or 32.6 light-years.
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