No-Instrument Sun Locating
Once you feel comfortable reading azimuths, altitudes/elevations, and your computer
sun position charts (print outs), No Instrument sun locating is possible. (
See "General Sun Information and "Sun Position Monograph")
Find a small yearly calendar and mark Dec 23 as mid winter, Feb 18 as early
spring, Mar. 23 as spring equinox, April 21 as early summer, June 23 as mid
summer, Aug. 22 as late summer, Sept. 23 as Fall equinox, and Oct. 24 as late
fall. If the sun is out, go out side and face to the South. At sun noon the
sun will be due south, 180 degrees, and at it's maximum altitude (height above
the true horizon) for the day.
Face to the South. If the date is near the equinoxes, Mar. 21 and Sept. 23,
the sun would have risen due east, 90 degrees, to your left and it will set
due west, 270 degrees, to your right. At noon it would have been 90 degrees
minus your latitude high above the horizon. For the first few hours the sun
will rise at an angle of 90 minus your latitude to the horizon. A few hours
before sunset this is also true.
Make an arc with your arm from sunrise due east on the horizon through the sun
where ever it is and over to sunset in the west on the horizon.
If its mid winter, Dec. and Jan., the sun will rise more than 23 degrees south
(right) of east and set more than 23 degrees south (left)of west and it will
only get 90 minus 23 minus your latitude above the horizon at noon and be due
south 180 degrees. It will rise and set less than 90 minus your latitude to
If it's mid summer, June and July, the sun will rise more than 23 degrees north
(left) of due east and will set more than 23 degrees north (right) of due west.
At noon it get as high as it ever gets in the sky all year above the horizon.
90 degrees plus 23 minus you latitude. It will rise and set at approximately
90 minus your latitude to the horizon.
If you are near Aug. 22 or April 22, the sun will be half way between the Equinoxes
positions and the mid summer June 5 to July 6 position.
If you are near Feb.18 and Oct.25, the sun will be half way between the Equinoxes
position and the mid winter, Dec. 7 to Jan 7 position. Now we have 5 different
arcs for the sun for different times of the year.
Remember, the sun stays south in the winter and north in the summer for more
days than it does in a position at the equinoxes. During the equinoxes the sun
changes sunrise and sunset azimuth as much as 1/2 degrees a day.
Before making any exact calculations, always do a seat-of-the-pants check to
get yourself oriented with your location.
With your computer sun position program calculate and print out for your location
Dec. 23, Feb. 16, Mar. 23, April 21, and June 23. Print out a "Monograph" and
enter the results for the above 5 dates. From summer to winter the sun "retreats"
on the same path. Label Feb. 12/Oct. 24, Mar.23/Sept.23, April 21/Aug.22 which
have the same position. The sun path graphs are not an accurate representation
of the sky because the sky curves in a hemisphere and the graph is flat like
a vertical wall. I know of no other way to represent this in two dimensions.
This monograph is a representation of the sky looking south and where the sun
is at different times of the year.
© Copyright 1999-2004 Ron Dexter. All Rights Reserved.