Photo location: Home of Susan R. overlooking the Hudson River in HOH.  I-Phone pic by james dean conklin, leader of Solar Punch, "SDC's official band" who WILL play at our yearly Summer Solstice Party at Maud's Tavern across from Train Station in Hastings-on-Hudson. 

Others wishing to Join:  $75 in advance

Open bar, munchees,  

choice of great entrée, dessert

email:   

jinhuang@sdcollab.com for availability and reservation 

The Non-Political Phenomena of  

Manhattanhendge  

Looking "West" during "Manhattanenge". Actually 29 degrees North of West

Should we thank Mayor Bloomberg for pushing through the "law" that provides for the poetic and this year well publicized "Manhattanhenge" display.  Maybe it was really the work of Fiorello or David Dinkins? All it really took was the logical development of Manhattan Island with major avenues running parallel to the Hudson River, with crosstown streets perpendicular to the avenues.

Apparent Sun Position

Many solar basics can be seen or deduced from the "Apparent" Sun Position diagram above that suffices for New York City (considered to be "40 degrees North latitude"). And remember,sun movement is always apparent - it's the earth that moves, not the sun. Working from the lowest "winter" sun path:

• In Winter, the sun rises far south of east.  And on the Winter Solstice (December 21st) the sun rises 31 degrees south of east - and sets, believe it or not, 31 degrees south of west.  The Noon altitude angle of the sun on the Winter Solstice is equal to: 90 - Latitude + declination = 90 - 40 + (-23.5) = 26.5 degrees (pretty low and casting long shadows - overhangs please).

• Spring and Fall, the sun rises generally easy and sets generally west.  On the Equinoxes (e.g., March 21st and September 21st) the sun rises precisely due east and sets due west.  And of course the sun is now much higher in the sky. The Noon altitude angle of the sun on the Equinoxes is equal to: 90 - Latitude + declination  = 90 - 40 + (-0)  = 50 degrees.

• In Summer, the sun rises north of east - and sets north of west maximizing on the Summer Solstice when the angle north of east and west is about 31 degrees.  Look at a google or any other accurately oriented map - Manhattan island and it's "N-S" streets run about 29 degrees to the west of south. Since on May 28th the sun sets 29 degrees north of west it can be seen directly at the end of the street grid.  The sunset then moves a little further north (31 degrees in New York) for the solstice, and then back to Manhattanhenge position by July 13th.   

Fascinating is the fact that the sunset angle only changes by about 2 degrees over 36 days (May 28th until July 13).  I learned long ago watching "The Lone Ranger" show that solstice means "when the sun stands still."  Very helpful to know in those barbaric "Pre-APP" days.  And no wonder why SDC has parties every year to celebrate the Summer and Winter Solstices.