sidereal hour angle
41Celestial coordinate system — For other uses of Celestial , see Celestial (disambiguation). Orientation of Astronomical Coordinates Orientation of the galactic, ecliptic and equatorial coordinate systems, projected on the celestial sphere, showing the galactic equator (black) …
42Meridian (astronomy) — This article is about the astronomical concept. For other uses of the word, see Meridian. The meridian is the outer orange circle which Z, the zenith, lies on. O is the observer. In the sky, a meridian is an imaginary great circle on the… …
43Conversion of units — is the conversion between different units of measurement for the same quantity, typically through multiplicative conversion factors. Contents 1 Techniques 1.1 Process 1.2 Multiplication factors …
44calendar — calendrical /keuh len dri keuhl/, calendric, calendarial /kal euhn dair ee euhl/, calendarian, calendaric, adj. /kal euhn deuhr/, n. 1. a table or register with the days of each month and week in a year: He marked the date on his calendar. 2. any …
45Minute — This article is about the unit of time, angle and right ascension. For other uses of the word, see Minute (disambiguation). See also: Minute of arc A minute is a unit of measurement of time or of angle. The minute is a unit of time equal to… …
46Year — A year (from Old English gēar) is the orbital period of the Earth moving around the Sun. For an observer on Earth, this corresponds to the period it takes the Sun to complete one course throughout the zodiac along the ecliptic. In astronomy, the… …
47Longitude — For Dava Sobel s book about John Harrison, see Longitude (book). For the adaptation of Sobel s book, see Longitude (TV series). Map of Earth Longitude (λ) Lines of longitude appear vertical with varying curvature in this projection, but are… …
48Solstice — For other uses, see Solstice (disambiguation). UTC date and time of solstices and equinoxes[1] year Equinox Mar Solstice June Equinox Sept Solstice Dec day time day time day time day time 2004 20 …
49Horoscope — In astrology, a horoscope is a chart or diagram representing the positions of the Sun, Moon, planets, the astrological aspects, and sensitive angles at the time of an event, such as the moment of a person s birth. The word horoscope is derived… …
50spaceflight — /spays fluyt /, n. the flying of manned or unmanned spacecraft into or in outer space. Also, space flight. [1945 50; SPACE + FLIGHT1] * * * Introduction flight beyond Earth s atmosphere. This article deals with the basic concepts associated with …
