celestial meridian

A star on the observer's celestial meridian is said to have a zero hour angle.

Time begins: once the sun has crossed the celestial meridian (true noon), exactly halfway between sunrise and sunset.

One of the new instruments was a small transit telescope used to observe the position of the stars as they cross the celestial meridian.

He commissioned several geographers to remeasure the distance on earth that corresponds to one degree of celestial meridian.

Except that the needle doesn't point precisely in the direction of the daystar, but toward the intersection of the celestial meridians.

The point of the vernal equinox falls on a celestial meridian which is assigned a value of O' right ascension.

This celestial meridian matches the projection, onto the celestial sphere, of the terrestrial meridian.

"That's an armillary sphere, depicting the celestial meridians, equators, tropics, and zodiac.

The shadowband is a strip of metal formed into a circular arc and mounted along a celestial meridian, with the instrument's entrance aperture at the center of the arc.

The celestial meridian 'L' passes through two notches in the north and south points of the horizon, as in a common globe: both here, if the globe be turned round, the horizon and meridian turn with it.

If instead of measuring from and along the horizon the angles are measured from and along the celestial equator, the angles are called right ascension if referenced to the Vernal Equinox, or hour angle if referenced to the celestial meridian.