Related Words

Perigee: The point nearest the earth on the moon's orbit. This term can be applied to any other body orbiting the earth, such as satellites. It is the opposite of apogee.

P: Fifth letter of Nasdaq stock symbol specifying issue is the company's first class of preferred shares.

P1: Rate of change (as of January 1, 1900) in mean longitude of solar perigee. P1 = 0.000,001,96° per solar hour.

Perigean Tides Or Tidal Currents: Tides of increased range or tidal currents of increased speed occurring monthly as the result of the Moon being in perigee. The perigean range (Pn) of tide is the average range occurring at . . . View Full Definition

Month: The period of the revolution of the Moon around the Earth. The month is designated as siderial, tropical, anomalistic, nodical, or synodical according to whether the revolution is relative t . . . View Full Definition

Parallax Inequality: The variation in the range of tide or in the speed of a tidal current due to changes in the distance of the Moon from the Earth. The range of tide and speed of the current tend alternately t . . . View Full Definition

Equilibrium Argument: The theoretical phase of a constituent of the equilibrium tide. It is usually represented by the expression (V+ u), in which V is a uniformly changing angular quantity involving multiples of . . . View Full Definition

Age Of Parallax Inequality: The time interval be tween perigee of the Moon and the maximum effect of parallax upon range of tide or speed of the tidal current. This age may be computed from the harmonic constants by th . . . View Full Definition

Anomalistic: Pertaining to the periodic return of the Moon to its perigee or the Earth to its perihelion. The anomalistic month is the average period of the revolution of the Moon around the Earth with r . . . View Full Definition

Anomaly: As applied to astronomy, the anomaly is the angle made at any time by the radius vector of a planet or moon with its line of apsides, the angle being reckoned from perihelion or perigee in t . . . View Full Definition