right ascension
3
9.4
- noun
- /raɪt əˈsɛnʃən/
- Specialized
:
ascensión recta
- The astronomer noted the right ascension of the planet to help other researchers track its movement across the night sky.
- right ascension and declination
- coordinates of right ascension
Examples
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In astronomy, right ascension is measured in hours and is crucial for pinpointing the location of celestial objects.
-
Examination of the Bright Star Catalogue revealed a star at right ascension 05h 36m 54.8s, declination -66 degrees 33' 37", magnitude 6.3.
Academic text (2000) -
At that moment, my local sidereal time would match the right ascension of that star.
Academic text (2002) -
Do you mind checking right ascension 18 hours, 34 minutes; declination plus 38 degrees, 41 minutes?
Fiction book (1997) -
Every year on the winter solstice, our Sun has a declination of -23.5 degrees and a right ascension of 18 hours.
Blog text (20) -
24 hours, at least in the modern definition, is the length of the solar day—the time required for the apparent motion of the Sun to return it to the same right ascension.
Blog text (11) -
After these coordinates had been calculated for all 66,725 earthquakes, I found the difference of the position of the sun/moon with respect to each earthquake in terms of right ascension.
Blog text (14) -
The coordinates are celestial coordinates; right ascension is the celestial longitude and declination is the celestial latitude.
Academic text (1990) -
To locate the star accurately, adjust the right ascension on your telescope until it aligns with the celestial coordinates.
Synonyms
17
9.8
The position of a star measured east along the sky's equator from the vernal equinox in hours, minutes and seconds
How far east a star or planet is along the sky's equator from the spring equinox
Surface Forms
Morphology
This is a specialized astronomical term whose sense (an angular coordinate measured eastward along the celestial equator) is not the straightforward sum of 'right' (usually 'correct' or 'the right-hand side') and 'ascension' ('rising'). A B1 learner who knows the constituent words would not be able to infer the technical meaning, since the phrase functions as a conventional terminological label in astronomy rather than a transparently compositional description.
Etymology
Right ascension may come from older words where right meant 'straight along' the sky's equator and ascension meant 'rising' in the sky. So the name gives an image: it measures how far east a star has 'risen' along that equator, and astronomers give that position often in hours like a clock.