- Aitken's criterion for double stars
- критерий двойных звезд Айткена
English-russian astronautics dictionary. - M.: Military Publishing house. Compiled by F. P. Suprun, K. V. Shirokov. 1964.
Orbit of the Moon — Not to be confused with Lunar orbit in the sense of a selenocentric orbit, that is, an orbit around the Moon The Moon completes its orbit around the Earth in approximately 27.3 days (a sidereal month). The Earth and Moon orbit about their… … Wikipedia
publishing, history of — Introduction an account of the selection, preparation, and marketing of printed matter from its origins in ancient times to the present. The activity has grown from small beginnings into a vast and complex industry responsible for the… … Universalium