Table 169 



EPHEMERIS OF THE SUN 1 



495 



All data are for 0* Greenwich Civil Time in the year 1950. Variations of these data from 

 year to year are negligible for most meteorological purposes, the largest variation occurs 

 through the 4-year leap-year cycle. The year 1950 was selected to represent a mean condition 

 in this cycle. 



The declination of the sun is its angular distance north ( + ) or south ( — ) of the celestial 

 equator. 



The longitude of the sun is the angular distance of the meridian of sun from the vernal 

 equinox (mean equinox of 1950.0) measured eastward along the ecliptic. 



The equation of time (apparent — mean) is the correction to be applied to mean solar time 

 in order to obtain apparent (true) solar time. 



The radius vector of the earth is the distance from the center of the earth to the center of 

 the sun expressed in terms of the length of the semimajor axis of the earth's orbit. 



1 U. S. Naval Observatory, The American ephemeris and nautical almanac for the year 1950, Washington, 

 1948. 



EPHEMERIS OF THE SUN 



Date 



SMITHSONIAN METEOROLOGICAL TABLES 



