Evidence also exists that alignments to the moonrise or moonset on the days of lunar standstills can be found in ancient sites of other ancient cultures, such as at Chimney Rock in Colorado and Hopewell Sites in Ohio. Major lunar standstill A major lunar standstill occurs when the Moon's declination reaches a maximum monthly limit, stopping at 28.725° north or south. An eclipse season near the March equinox has solar and lunar eclipses at an odd-numbered saros, while another eclipse season near the September equinox has solar and lunar eclipses at an even-numbered saros. Between 1951 and 2050, these dates are 29 March 1969, 8 November 1987, 19 June 2006, 29 January 2025 and 10 September 2043. Minor lunar standstill A minor lunar standstill occurs when the Moon's declination reaches a minimum monthly limit, stopping at 18.134° north or south. An eclipse season near the March equinox has solar and lunar eclipses at an even-numbered saros, while another eclipse season near the September equinox has solar and lunar eclipses at an odd-numbered saros. Between 1951 and 2050, these dates are 7 December 1959, 19 July 1978, 27 February 1997, 10 October 2015 and 21 May 2034. Origin of name The term lunar standstill was apparently first used by engineer Alexander Thom in his 1971 book Megalithic Lunar Observatories. The term solstice, which derives from the Latin solstitium: sol- (sun) + -stitium (a stoppage), describes the similar extremes in the Sun's varying declination. Neither the Sun nor the Moon stands still, obviously; what stops, momentarily, is the change in declination. The word tropic, as in Tropic of Capricorn, comes from ancient Greek meaning "to turn", referring to how ascending (or descending) motion turns to descending (or ascending) motion at the solstice. Informal explanation As Earth rotates on its axis, the stars in the night sky appear to follow circular paths around the celestial poles. (This daily cycle of apparent movement is called diurnal motion.) All the stars seem fixed on a celestial sphere surrounding the observer. In the same way that positions on Earth are measured using latitude and longitude, the apparent places of stars on this sphere are measured in right ascension (corresponding to longitude) and declination (corresponding to latitude). If viewed from a latitude of 50° N on Earth, any star with a declination of +50° would pass directly overhead (reaching the zenith at upper culmination) once every sidereal