uranology

phase - (astronomy) the particular appearance of a body's state of illumination (especially one of the recurring shapes of the part of Earth's moon that is illuminated by the sun); "the full phase of the moon"

absolute magnitude - (astronomy) the magnitude that a star would have if it were viewed from a distance of 10 parsecs (32.62 light years) from the earth

Hubble law, Hubble's law - (astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer

Kepler's law, Kepler's law of planetary motion - (astronomy) one of three empirical laws of planetary motion stated by Johannes Kepler

Copernican system - (astronomy) Copernicus' astronomical model in which the Earth rotates around the sun

Ptolemaic system - (astronomy) Ptolemy's model of the universe with the Earth at the center

natural philosophy, physics - the science of matter and energy and their interactions; "his favorite subject was physics"

astrodynamics - the branch of astronomy that studies the motion of natural and artificial bodies in space

astrometry - the branch of astronomy that deals with the measurement of the position and motion of celestial bodies

radio astronomy - the branch of astronomy that detects and studies the radio waves emitted by celestial bodies

celestial mechanics - the branch of astronomy concerned with the application of Newton's laws of motion to the motions of heavenly bodies

astrophysics - the branch of astronomy concerned with the physical and chemical properties of celestial bodies

selenology - the branch of astronomy that deals with the moon

solar physics - the branch of astronomy that deals with the sun

ascension - (astronomy) the rising of a star above the horizon

egress, emersion - (astronomy) the reappearance of a celestial body after an eclipse

ingress, immersion - (astronomy) the disappearance of a celestial body prior to an eclipse

alignment, conjunction - (astronomy) apparent meeting or passing of two or more celestial bodies in the same degree of the zodiac

inferior conjunction - (astronomy) the alignment of the Earth and a planet on the same side of the sun

superior conjunction - (astronomy) the alignment of the Earth and a planet on the opposite side of the sun

Oort cloud - (astronomy) a hypothetical huge collection of comets orbiting the sun far beyond the orbit of Pluto; perturbations (as by other stars) can upset a comet's orbit and may send it tumbling toward the sun

extragalactic nebula, galaxy - (astronomy) a collection of star systems; any of the billions of systems each having many stars and nebulae and dust; "`extragalactic nebula' is a former name for `galaxy'"

apoapsis, point of apoapsis - (astronomy) the point in an orbit farthest from the body being orbited

node - (astronomy) a point where an orbit crosses a plane

equinoctial point, equinox - (astronomy) either of the two celestial points at which the celestial equator intersects the ecliptic

vernal equinox - (astronomy) the equinoctial point that lies in the constellation of Pisces

autumnal equinox - (astronomy) the equinoctial point that lies in the constellation of Virgo

barycenter - (astronomy) the common center of mass around which two or more bodies revolve

culmination - (astronomy) a heavenly body's highest celestial point above an observer's horizon

limb - (astronomy) the circumferential edge of the apparent disc of the sun or the moon or a planet

periapsis, point of periapsis - (astronomy) the point in an orbit closest to the body being orbited

anomaly - (astronomy) position of a planet as defined by its angular distance from its perihelion (as observed from the sun)

celestial latitude, dec, declination - (astronomy) the angular distance of a celestial body north or to the south of the celestial equator; expressed in degrees; used with right ascension to specify positions on the celestial sphere

celestial longitude, right ascension, RA - (astronomy) the equatorial coordinate specifying the angle, measured eastward along the celestial equator, from the vernal equinox to the intersection of the hour circle that passes through an object in the sky; usually expressed in hours and minutes and seconds; used with declination to specify positions on the celestial sphere; "one hour of right ascension equals fifteen degrees"

asterism - (astronomy) a cluster of stars (or a small constellation)

canal - (astronomy) an indistinct surface feature of Mars once thought to be a system of channels; they are now believed to be an optical illusion

coma - (astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed

comet - (astronomy) a relatively small extraterrestrial body consisting of a frozen mass that travels around the sun in a highly elliptical orbit