deff: a person trained for or engaged in space flight

deff: an expert in astronomy

deff: the science that deals with the material universe beyond Earths atmophere

deff: the line about which a rotating body, such as Earth

deff: any various groups of stars to which have been given names

deff: part way between a half moon and a full moon

deff: when the Moon blocks the Suns rays

deff: an imaginary circle around the Earth

deff: the two times of the year when day and night are equal length

deff: the attraction of bodies by gravitation towardthe center of Earth

deff: one of the halves of the Earth as divided by the equator

deff: phases of the moon that occur at different times of the month

deff: the action by a celestial body of going round in a fixed course

deff: to turn about an axis or a center