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P3D Re: Parallax tech

  • From: Chris Jones <c.jones@xxxxxxxxx>
  • Subject: P3D Re: Parallax tech
  • Date: Wed, 1 Dec 1999 06:12:21 -0700
At 05:06 01/12/99 -0700, Gregory wrote:
>If you're referring to the "parsec", that's a unit of distance, not
>a parallax measurement: a parsec is defined as the distance at which the
>PARallax (of a star) would be one SECond of arc, with the diameter of the
>earth's orbit as the base.

Nearly - the base is the radius of Earth's orbit (half the diameter), aka
the Astronomical Unit. I think astronomers just liked drawing right-angled
triangles ;)

(for numberheads, 1AU = 1.496e11m, so 1pc = 3.086e16m)

But you're right, parallax is an entirely general term, not specific to
astronomy.

-- 

Chris Jones 
http://www.c.jones.cwc.net
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