The Tropic of Capricorn is a latitude approximately 23°27′ S of the terrestrial Equator. This latitude corresponds to the southernmost declination of the Sun’s ecliptic to the celestial equator. At the winter solstice (Northern Hemisphere), around December 21, the Sun is directly over the Tropic of Capricorn and lies within the boundaries of the constellation Sagittarius, having reached its southernmost declination in the ecliptic. Previously, however, it appeared in the constellation Capricornus at the winter solstice, hence the name Tropic of Capricorn. (Source Encyclopaedia Britannica)