Sun

from marv klotz

The program is based on information found in:

Almanac for Computers for the year 1978

published by the

In this publication, two types of series expansions are presented. A short term Chebyshev series valid only for 1978 is useless for long term computation. However, a much more complex trigonometric series is described which is valid for a 300 year span 1800-2100. It is this latter series that is implemented in the program. The Almanac lists the following accuracies for computed quantities:

Latitude is measured positive north of the equator, negative south of the equator - permissible range is -90 <= latitude <= 90 deg.

Longitude is measured positive WESTWARD from Greenwich, negative eastwards - permissible range is -180 <= longitude <= 180 deg.

One way to get fairly accurate values for lat and lon is to find someone who has a GPS (Global Positioning System) receiver and ask him to take a reading. Your local airport may also be able to supply accurate values.

UT (Universal Time) offsets are measured negative westward from Greenwich. In the absence of any daylight saving adjustments, Los Angeles time = Universal time - 8 hours (i.e., it's 8 hours earlier in LA than it is in London). The correct values for the conus time zones are shown below.

Eastern time zone

-5,-4

Central time zone

-6,-5

Mountain time zone

-7,-6

Pacific time zone

-8,-7

Note that UT is not ALWAYS the same as the time in London. UT NEVER 'goes on daylight savings'. The British DO employ daylight savings (I think it's called something like 'British Summer Time'). If you have access to a short-wave receiver capable of receiving WWV or WWVH (the USNBS time broadcast stations), you can determine UT from their transmissions. Alternatively, with a web browser, go to:

http://www.hilink.com.au/times/

and you can determine UT as well as local time in many locations around the world.

If daylight savings is not used in your area (e.g., Hawaii), enter the same value as used for the standard time offset. Some areas of the world have half hour offsets - enter as a decimal fraction, e.g., -9.5 hr.

If standard or daylight savings times are preceeded by '<' (e.g. < ST) they refer to that time on the previous day.)