The viewing oval (click to enlarge).
The Robbins Farm Park web site explains what the project is about.
Here
What are the geographic coordinates of the oval at Robbins Farm Park?
North 42d 24m 48.4668s = 42.413463
West -71d 10m 30.0822s = -71.175023
Which way is North?
That is left as an excercise for the reader.
What is an analemmatic sundial? Look at the Sundial Primer.
Here
My Java program to compute an analemmatic dial.
Here
Computation for a 3 meter dial on the time zone meridian.
Command line: java Analemmatic 42.413 75.0 3.0
Here
Computation for a 3 meter dial at Robbins Farm adjusted for longitude.
Command line: java Analemmatic 42.413 71.175 3.0
Here
Plot of the points of an adjusted dial.
Here
The earlier computation for an uncorrected 3 meter dial.
Here
Table of solar declination.
Here
NOAA web site for computing Solar Noon and the Equation of Time.
Here
Solar Noon on October 18th is at 12:29:49.
The Equation of Time on October 18th is 14.87 minutes.
Why does Solar Noon change every day and why the earliest sunset
and latest sunrise don't happen on the shortest day?
Here
or
Here
Will it be clear at noon tomorrow? Look at the Clear Sky Clock.
Here
North American Sundial Society (NASS)
Here
A page on the history of sundials and a lot of sundial links.
Here
The Amateur Telescope Makers of Boston, Bostons big astronomy club.
Here
Stellafane, the big amateur astronomers convention in Vermont.
Here
Public events at the Center for Astrophysics in Cambridge.
Here
Sundial pictures that I have taken.
Here
MIT Henge, where the setting sun aligns with the Infinite Corridor
on November 11th and January 30th.
Here
A sun position calculator (click to enlarge). The cursor is set to
the date and time and the azimuth and altitude of the sun are then
shown.
A Java applet that shows how the hour lines of a horizontal sundial
change with latitude. Your browser must support Java.
Here
