The Day of the Sun's Return, The Winter Solstice Montgomery College Planetarium at Takoma Park/Silver Spring http://ww2.montgomerycollege.edu/Departments/planet By Dr. Harold Williams December 21, 2016 version

One People … One Sky …Two Seasons http://www.astronomerswithoutborders.org/images/stories/SwB/SwB4_print.jpg

1980 Winter Solstice at Stonehenge

Lawrence Hall of Science, CA Sunstone, resent

Amaterasu appearing from the cave on the Winter Solstice

Citron hot water of the Winter Solstice Yuzuyu, Katori City Japan

Locri Pinax Persephone Opens Likon Mystikon. http://en.wikipedia.org/wiki/Persephone

Frederic Leighton-The Return of Persephone (1891) FredericLeighton-TheReturnofPerspephone(1891) http://en.wikipedia.org/wiki/Persephone

Length of Seasons Summer 93 days 15 hours 29 minutes Autumn 89 days 20 hours Winter 88 days 23 hours 54 minutes Spring 92 days 18 hours 26 minutes Sun and Earth closest, perihelion Around January 3 or 4 Sun and Earth furtherest, aphelion Around July 4

Obliquity of the ecliptic 23 ½ degrees, approximately, between day axis of rotation and year axis of revolutionary orbit about the sun Causes the seasons Seasons are not caused by the fact that the Earth’s orbit is not a perfect circle, but its orbit is slightly elliptical. This ellipticity of the Earth orbit does cause the seasons which are caused by the tilt, obliquity of the ecliptic, to be slightly unequal in length.

Seasonal Years Mean tropical year is 365.242 189 670 SI days vernal equinox: 365.24237404 + 0.00000010338×a days northern solstice: 365.24162603 + 0.00000000650×a days autumn equinox: 365.24201767 − 0.00000023150×a days southern solstice: 365.24274049 − 0.00000012446×a days Average tropical year is 365.2422 currently. as in Julian years from 2000 http://en.wikipedia.org/wiki/Tropical_year (a in Julian years from 2000)

Winter Solstice Links http://en.wikipedia.org/wiki/Shortest_day

How to tell time http://en.wikipedia.org/wiki/Equation_of_time Using the sun and moving to uniform watch time! Until 1833, the equation of time was tabulated in the sense 'mean minus apparent solar time' in the British Nautical Almanac and Astronomical Ephemeris published for the years 1767 onwards. Before the issue for 1834, all times in the almanac were in apparent solar time, because time aboard ship was most often determined by observing the Sun.

Equation of Time Graph showing the equation of time (red solid line) along with its two main components plotted separately, the part due to the obliquity of the ecliptic (mauve broken line) and the part due to the Sun's varying apparent speed along the ecliptic due to the eccentricity & ellipticity of the Earth's orbit (dark dash-dotted line) http://en.wikipedia.org/wiki/File:Zeitgleichung.png used in http://en.wikipedia.org/wiki/Equation_of_time