The Sun
Distance: 147-152 million km.
Diameter: 1.4 million km.
Apparent cross-section: About 0.53 degrees.
Notes: Strictly speaking of course, the sun does not orbit the earth.
As explained by James Miller (see below), the Sun's position can be computed as
if it
did. A sample Keplerian Element file
is included with the program if you would like to experiment. However,
WinOrbit predicts the Sun's position using a trigonometric series
expansion (sine and cosine terms) such as that published in the Astronomical
Almanac. Note that the Sunrise and Sunset times (AOS/LOS) published in the
Astronomical Almanac, World Almanac, and other tabulations, assume a particular
atmospheric refraction,
and allow for the width of the solar disk, so that the edge of the sun is
visible when the center is still about 0.8 degree below a level horizon.
WinOrbit makes no such assumption and reports the "true" position of the
center of the sun's disk. The distance reported is to the center, likewise
ignoring the substantial radius of the sun.
Tracking the Sun with WinOrbit: The sun and moon will be found in the
Tracking
list in the Main Window ahead of any satellite maps. They are also
found in the Satellite Selection list in the
Print Dialog Box.
References:
"Keplerian Elements for the Sun", James Miller, G3RUH,
Amateur Satellite Report, no. 137, December 1, 1986, p. 4.
"Pathfinder: Improved Minimuf Program", Ron Todd, K3FR , ham radio, May 1988, p. 26; and October 1988, p. 47.
"World Almanac and Book of Facts 1995", Funk and Wagnalls, Mahwah, NJ, 1994, p. 267-285.
"Astronomical Almanac for the Year 1994", US Government Printing Office, Washington, 1993, p. C24. (A new edition is published each year).
Satellite List
Converted by Winhelp to Web