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International Sunbeam and Shadow Project “Sun 45 Equi-umbra”

Equi-umbra, Sunrise, Transit and Sunset Information

1. Obtaining Sun Tables from US Naval Observatory (USNO)
Quick Easy Free : simply go to a USNO webpage, put simple information into a few little boxes, and quickly down load an easy to read table.

Example: Washington DC, date 2009 July 4

We want to obtain:

  • time of sunrise and the horizontal angle from north (azimuth) of the sun on the horizon
  • time of morning equiumbra (altitude = 45 degrees before noon) and the sun's azimuth.
  • time and altitude of the sun at noon when the sun is due south (azimuth = 180 degrees)
  • time of afternoon equiumbra (altitude = 45 degrees after noon) and the sun's azimuth.
  • time of sunset and azimuth.
Go to the US Naval Obesrvatory sun / moon information page by clicking here.

Scroll down to: Form A - U.S. Cities or Towns

Click circle Object: Sun

Insert year: 2009
Insert month: July
Insert day:4

Insert state name: District of Columbia

Insert city name: "Washington"

Insert time interval (minutes): 1

Click Compute

A new page should appear with a table, titled as above.

Altitude/Azimuth Table for One Day
Astronomical Applications Dept.                                               
U.S. Naval Observatory                                                        
Washington, DC 20392-5420
WASHINGTON, DISTRICT OF COLUMBIA                                              
   o  ,    o  ,                                                               
W 77 02, N38 53
Altitude and Azimuth of the Sun                                               
Jul 4, 2009                                                                   
Eastern Standard Time
          Altitude    Azimuth                                                 
                      (E of N)
 h  m         o           o                                                   
From the table all the information required can easily be obtained see link below

If the following appears:

Unable to find location in our file.  Try another location.
it is probable that the location is not on the computer's database.

If this is the case or if you want to obtain data for this or for any other location worldwide go back to the form page and scroll down to:

Form B Locations Worldwide.

In processing Form A, the computer inserted the latitude and longitude automatically from its data base.

With Form B users have to insert the latitude and longitude , of the location themselves.
The values in units of degrees and minutes must be inserted in the respective boxes.

The name of the location has also to be inserted. This will appear at the head of the table.

As a check, and for possible use when copy and pasting, We find it useful to insert the latitude and longitude in degrees-minutes, in the same box as the name of the location

for example     N 41-52 E 12-37 Rome            

Next 2. Easy Reading of Sun Tables from USNO


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