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1995-05-25
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133 lines
SSSSUUUUNNNNCCCCLLLLOOOOCCCCKKKK((((GGGG)))) UUUUNNNNIIIIXXXX VVVV SSSSUUUUNNNNCCCCLLLLOOOOCCCCKKKK((((GGGG))))
NNNNAAAAMMMMEEEE
sunclock - show illuminated portion of Earth
SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS
ssssuuuunnnncccclllloooocccckkkk [ _o_p_t_i_o_n_s ]
DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
_s_u_n_c_l_o_c_k 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.
OOOOPPPPTTTTIIIIOOOONNNNSSSS
The program does not use the X Toolkit, and hence only those
options explicitly enumerated below may be used. Neither
are any resources used.
----vvvveeeerrrrssssiiiioooonnnn
Show program version and patch level, and then exit.
----ddddiiiissssppppllllaaaayyyy _d_i_s_p_n_a_m_e
Give the name of the X server to contact.
----iiiiccccoooonnnniiiicccc
Start iconic. Usually you will want to specify this
option.
----ggggeeeeoooommmmeeeettttrrrryyyy +_x+_y
Specify the position of the window. Only the position
is used; any size information given is ignored.
----iiiiccccoooonnnnggggeeeeoooommmmeeeettttrrrryyyy +_x+_y
Specify the position of the icon. Only the position is
used; any size information given is ignored.
HHHHOOOOWWWW IIIITTTT WWWWOOOORRRRKKKKSSSS
_s_u_n_c_l_o_c_k calculates the position of the Sun using the
algorithm in chapter 18 of:
_A_s_t_r_o_n_o_m_i_c_a_l _F_o_r_m_u_l_a_e _f_o_r _C_a_l_c_u_l_a_t_o_r_s 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.
BBBBUUUUGGGGSSSS
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.
Page 1 (printed 2/21/91)
SSSSUUUUNNNNCCCCLLLLOOOOCCCCKKKK((((GGGG)))) XXXXEEEENNNNIIIIXXXX SSSSyyyysssstttteeeemmmm VVVV SSSSUUUUNNNNCCCCLLLLOOOOCCCCKKKK((((GGGG))))
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.
AAAAUUUUTTTTHHHHOOOORRRR
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>.
Page 2 (printed 2/21/91)