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


">
" size=20>

 
 

Browse articles alphabetically:
#0">0 | #1">1 | #2">2 | #3">3 | #4">4 | #5">5 | #6">6 | #7">7 | #8">8 | #9">9 | #_">_ | #A">A | #B">B | #C">C | #D">D | #E">E | #F">F | #G">G | #H">H | #I">I | #J">J | #K">K | #L">L | #M">M | #N">N | #O">O | #P">P | #Q">Q | #R">R | #S">S | #T">T | #U">U | #V">V | #W">W | #X">X | #Y">Y | #Z">Z