
SunDial h  A#  h#  F#  DL#  X# XS# Y# YS# TA#  R#  {S/B} W[output file name]
   L# Ddd[.mm[.yy] Thh[.mm[.ss]] UT# AL# P# {Left/Right} M#
   E[<name>[:<name>]] AB# N# Q
  { PT[LaTeX picture file name] / PP[Encapsulated PostScript file name] }
plots a sundial on the screen. Parameters (on the first line) are:

H   writes this information into SunDial.hlp
A   Azimuth of the direction perpendicular to the sundial plane (default 180=S)
h#  angular height of that direction /1 degree (default 0, i.e. vertical wall)
F#  latitude (in degrees, too; default 49.20 = latitude of Brno)
DL# How many minutes is the local time ahead of that which you want to plot
DD#[:#] ``Declinations / 1 degree' for hour lines description, default
 -33:33
X#  horizontal shift of the plot in percent of the screen width
XS# side along X coordinate (default 100 per cent of the screen)
Y#  vertical   shift of the plot in percent of the screen height
YS# side along Y coordinate (def. 94 % for VGA to match A4 landscape)
TA# is the "hour" along which the analema (the "8") is to be plotted
R#  is the "Radius of projection" = magnification (default 1)
C#  implies a cylinder instead of a plane; # is its radius relative to R
S   asks for a Short description instead of a long one.
B   asks for a short description on the Bottom of the screen
BR- plots no border (BC would plot a circular border)
W<name> asks for making an output file <name> (default SunDial.txt)

The parameters on the second line concern the case, that the Azimuth
of the plane is not known, but its angle towards the Sun in some
instant is. The time is to be given in that case at least; the other parameters
have some default values.

L#  is the Longitude of the place / 1 degree, western as negative, default 16.60
D#  the Date (missing values are taken from the system date)
T#  the Time of observation
UT# is the t-UTC difference / 1 h (default 1 from Nov. to March, else 2)
AL# distance between the shadow tip and the foot of its source
   (ALong the plane, default 1)
P#  how much is the shadow tip nearer to the plane then its source
   (default 0, i.e. Sun lies just within the plane)
Left/Right - whether the Sun was to the left or right (default Left)

When the sun shines onto the plane almost tangentially, you can measure
AL and P in such a way: press two matchboxes to the plane some one meter
apart and so, that the first bow casts shadow on the second one.

In another cases, when the shadows are not that long, but still changing
their length with time sufficiently, press a pair of rectangles to the plane
so that they stay perpendicular to the plane. One rectangle should have
a circular hole near its end, and should face the Sun.
Mark by the pencil the foot of the shadow-casting rectangle
and the centre of spot of light cast through the hole.
Then note the time, and measure the distance (AL) of the spot from the
projection of the hole (it lies inside the outline of foot of rectangle).
The quantity P is the distance of the centre of hole from the plane (given
by the rectangle dimensions).

M#  9 (default) or 24 needle printer for hardcopy; Ctrl+PrintScreen or P
 makes hardcopy to "prn", any # to file named Sundial.e9 (or *.e24)
 in the TEMP directory (M1 asks for a CS212-25 printer)
PT output file with a LaTeX version of the screen (default screen.tex)
PP -     "     -    an Encapsulated PostScript -  "  -     screen.eps)
 LA prepend the above eps file with a prologue for a landscape print
SVGA#    or
SVGA256:# Try SVGA 256-color mode # (default 4 for the 1024x768 resolution
                                3 would set the 800x600 mode)
SVGA16:# is a 16 color alternative for 0.5 MB cards
SVGA:#   is another 256-color alternative, if you have svga.bgi
  Caution, some cards lock up the computer so that just RESET helps.
  (For the Free Pascal Compiler, the SVGA option is obsolete
   as the executable uses some VESA mode in any case.)

In the resulting plot, the pole is shown as a circle, the cross gives
  the projection of the "gnomon", the shadow-casting point, of the sundial,
  the line on the right side is its distance from the sundial.
The "hour lines" are given for each degree of the declination of the Sun,
the "hyperboles" are given for solar ecliptical longitude = n * 30 degrees
                           and for each 10 minutes.
The "8" shows the difference of the true and mean solar time - the arrow
  connects Oct. 11 and 21 (dots are shown for 1.,11. and 21. of each month)

E[<name>[:<cf_name>]  shows an exposure table afterwards,
  <name> is a name of file to which the information should be appended,
          <cf_name> is a name of file of the same structure, which should
          serve as a comparison (default comparison is for
          45 degrees over south at latitude 49.20 degrees).
 This is for evaluation of solar collectors and windows. Further parameters
 for this purpose are:
AB# absorption of radiation in glass at normal incidence (default 0.10)
N#  refractive index of glass (default 1.5, as an average for solar spectrum)
Z#[mag|%]  is extinction of solar radiation for Sun in zenith
    (default 0.3 mag, i.e. 24%; default unit is 1 magnitude for #<2
                                and 1 cmag otherwise)

Q   batch mode: do not wait for a pressed key at the end
No parameters are obligatory, ? gives this help

( (C) Jan Hollan, N.Copernicus Observatory and Planetarium in Brno, 1999-2004;
 subject to the GNU General Public License, http://www.gnu.org/copyleft;
 source code available at http://astro.sci.muni.cz/pub/hollan/programmes)
