stats-equation-of-time

THE EQUATION OF TIME ~ E O T

Astronomical EOT and solstice and equinox information:-

Explanatory article extracted from Illustrating Time's Shadow

A good web site for the EOT and analemma

Complete EOT spreadsheet with all formulae
which is invoked by   this main spreadshee t

*** NOTE *** always download first and then use a spreadsheet, never run it online without downloading. (sheet hyperlink issues)

*** NOTE *** an EOT sheet exists that incorporates both EOT and longitude, to generate a table to correct dials designed with no
longitude correction built in. Excel version is here, and is Open Office compatible. This is also in the main spreadsheets. These
however have an EOT graph to show the total EOT correction.

For general purposes, the tables rotate every four years

Also, note that almanacs exist in Euler, Scilab, DeltaCAD as well as
for the S mart Phones in .XLS form

DeltaCAD almanacs depict EOT graphically or as tables.

This analemma page discusses the dial plate furniture to depict the
EOT, known as the analemma, and has notes on analemma
construction and issues as well.

     5th         15th        25th
JAN         5.1         9.0        12.0
FEB        13.9        14.2        13.4
MAR        11.9         9.3         6.3
APR         2.8         0.0        -2.3
MAY        -3.6        -4.0        -3.5
JUN        -2.0        -0.1         2.0
JLY         3.9         5.3         5.9
AUG         5.4         3.8         1.4
SEP        -2.2        -5.8        -9.4
OCT        -12.7       -15.1       -16.5
NOV        -16.5       -15.1       -12.5
DEC        -8.8        -4.5         0.2

A helpful EOT table for the 5th, 15th, and 25th of
each month, for a generic year.

An EOT table using copper wire, copper tube (1/4 inch), and a glass backing.
Sun slow (+ve EOT) on top, sun fast (EOT -ve) on bottom. And the 12 months
are displayed horizontally. The time scale is 5, 10, and 15 minutes.

EOT 2016
EOT 2020

Explanatory article extracted
from Illustrating Time's
Shadow that discusses in
simple terms why the
equation of time exists, in
other words, why the sun's
time does not match a clocks
time.