Encyclopedia > Right ascension

  Article Content

Right ascension

Right ascension (RA) is an astronomical term associated with the equatorial coordinate system. RA is comparable to longitude, measured from a zero point known as the vernal equinox point. RA is measured in hours, minutes, and seconds; with one hour equal to 15 degrees.

RA can be used to determine a star's location and to determine how long it will take for a star to reach a certain point in the sky. For example, if a star with RA = 01:30:00 is at your zenith, then a star with RA = 20:00:00 will be directly overhead in 18.5 sidereal hours.

See also: declination



All Wikipedia text is available under the terms of the GNU Free Documentation License

 
  Search Encyclopedia

Search over one million articles, find something about almost anything!
 
 
  
  Featured Article
Wheatley Heights, New York

... median income for a household in the town is $75,076, and the median income for a family is $79,745. Males have a median income of $46,444 versus $34,000 for ...

 
 
 
This page was created in 37.9 ms