The Twenty-Eight Mansions (, " �rsh�b Xi?" ) form an ecliptic coordinate system used for those stars not visible ( from China ) during the whole year, based on the movement of the moon over a lunar month.
32.
The concept of right ascension has been known at least as far back as Hipparchus who measured stars in equatorial coordinates in the 2nd century BC . But Hipparchus and his successors made their star catalogs in ecliptic coordinates, and the use of RA was limited to special cases.
33.
The data was used to construct a model for the asteroid, revealing it to be a regular-shaped object, spinning about a pole with ecliptic coordinates ( ?, ? ) = ( + 20? 356?), although this is with an accuracy of only ?0?
34.
For travel between planets I'd use ecliptic coordinates, but if you're orbiting a planet then a system based on the planet's center and rotation axis is likely to be more useful . talk ) 06 : 02, 25 June 2015 ( UTC)
35.
In the ecliptic coordinate system, latitude ( ? ) and longitude ( ? ); in the horizon system, altitude ( Alt ) and azimuth ( Az ); and in the equatorial coordinate system, declination ( ? ), are all measured in degrees, arcminutes and arcseconds.
36.
However, Babylonian techniques of observational measurements were in a rudimentary stage of evolution and they measured the position of a planet in reference to a set of " normal stars " close to the ecliptic ( ??of latitude ) as observational reference points to help positioning a planet within this ecliptic coordinate system.
37.
Astronomical latitude is not to be confused with declination, the coordinate astronomers use in a similar way to specify the angular position of stars north / south of the celestial equator ( see equatorial coordinates ), nor with ecliptic latitude, the coordinate that astronomers use to specify the angular position of stars north / south of the ecliptic ( see ecliptic coordinates ).
