A great circle in the celestial sphere passing through the zenith and the east and west points of the horizon.
〔天文〕卯酉圈
Example sentencesExamples
Regiomontanus, however, is based upon an equal division of the equator rather than the prime vertical - it is the same method as that suggested by Morinus, but bows to convention by commencing from the ascendant.
For the observations closer to the meridian than the prime vertical, make the calculation of latitude with the estimated longitude.
For star observations a star should be selected which will be about three hours from the meridian and near the prime vertical at the times of observation.