Date: Sat, 19.09.20 02:26
Daily APOD Report
Discover the cosmos! Each day a different image or photograph of our
fascinating universe is featured, along with a brief explanation
written by a professional astronomer.
2020 September 19
Orion in Depth
Illustration Credit & Copyright: Ronald Davison
Explanation: Orion is a familiar constellation. The apparent positions
of its stars in two dimensions create a well-known pattern on the bowl
of planet Earth's night sky. Orion may not look quite so familiar in
this 3D view though. The illustration reconstructs the relative
positions of Orion's bright stars, including data from the Hipparcus
catalog of parallax distances. The most distant star shown is Alnilam.
The middle one in the projected line of three that make up Orion's belt
when viewed from planet Earth, Alnilam is nearly 2,000 light-years
away, almost 3 times as far as fellow belt stars Alnitak and Mintaka.
Though Rigel and Betelgeuse apparently shine brighter in planet Earth's
sky, that makes more distant Alnilam intrinsically (in absolute
magnitude) the brightest of the familiar stars in Orion. In the
Hipparcus catalog, errors in measured parallaxes for Orion's stars can
translate in to distance errors of a 100 light-years or so.
Tomorrow's picture: breaking distant light
Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
A service of: ASD at NASA / GSFC
& Michigan Tech. U.
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