SUNCLOCK
Section: User Commands (1)
Index
Return to Main Contents
NAME
sunclock - show illuminated portion of Earth
SYNOPSIS
sunclock
[
options
]
DESCRIPTION
sunclock
is an X11 application that displays a map of the Earth and
indicates the illuminated portion of the globe by drawing
sunlit areas dark on light, night areas as light on dark.
It also displays the current date and time.
OPTIONS
The program does not use the X Toolkit, and hence only those
options explicitly enumerated below may be used. Neither are
any resources used.
- -version
-
Show program version and patch level, and then exit.
- -display dispname
-
Give the name of the X server to contact.
- -iconic
-
Start iconic. Usually you will want to specify this option.
- -geometry +x+y
-
Specify the position of the window. Only the position is used; any size
information given is ignored.
- -icongeometry +x+y
-
Specify the position of the icon. Only the position is used; any size
information given is ignored.
HOW IT WORKS
sunclock
calculates the position of the Sun using the algorithm in chapter 18 of:
Astronomical Formulae for Calculators
by Jean Meeus, Third Edition, Richmond: Willmann-Bell, 1985.
and Mercator projects the illuminated area onto map image. The
Sun's position is calculated to better than one arc-second
in accuracy.
BUGS
The maps are not rescaled if you resize the open window or icon. (I don't want
to have to store a vector database for the map.) The program contravenes
section 4.1.9 of the ICCCM in that its icon window is a fixed size, and any
WM_ICON_SIZE property of the root window is ignored.
The illuminated area shown is the area which would be sunlit
if the Earth had no atmosphere. The actual illuminated area is
larger because of atmospheric refraction and twilight.
AUTHOR
John Mackin, Basser Department of Computer Science, University of Sydney,
Sydney, Australia; <john@cs.su.oz.AU>. Based on a Suntools program
by John Walker, Autodesk, Inc.; <kelvin@acad.uu.NET>.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- HOW IT WORKS
-
- BUGS
-
- AUTHOR
-
This document was created by
man2html,
using the manual pages.
Time: 20:43:53 GMT, June 11, 2022