parallax second

1 definition found

parallax second - Collaborative International Dictionary of English v.0.48 :

  parallax second \par"al*lax sec"ond\, n.
     An annual parallax of one second of an arc; -- applied to
     celestial objects outside the solar system. It is used to
     measure the distance of an astronomical object from the
     Earth. A star which has an annual parallax of one second of
     an arc is considered to be one parsec (3.26 light years)
     distant from the earth. See parsec in the vocabulary.
     [PJC]