    SUNDIALS - DEMO - v. 1/97
    ==========================

    This group of programs (working in DOS) is useful to calculate data for
    many kinds of Sundial,  to print them, to plot the Sundial's hour-lines
    and daily-lines ,to print the drawing and to see ( on the drawings) how
    the shadow changes with time.

    The Sundials that can be calculated are:

       - FLAT SUNDIALS       Plane Whatever, projecting point whatever
      
       - BIFILAR SUNDIALS  ( MICHNIK )
         The Shadow-Point is the intersection of the shadows of two Straight
         Lines on a plane

       - SUNDIALS (on a plane) with old hours: ITALIAN, BABYLONIAN,TEMPORARY

       - MONOFILAR SUNDIALS
         Shadow-Point is the intersection of the shadow of a Straight Line
         with daily Lines of peculiar forms

       - SUNDIALS ON VERTICAL CYLINDER  -  EXTERNAL - INTERNAL SURFACE
         Fixed Cylinder-Fixed Rod, Fixed Cylinder-Movable Rod, Hat S.,
         Shepherd's S.

       - SUNDIALS ON HORIZONTAL CYLINDER - EXTERNAL - INTERNAL SURFACE
         Fixed Cylinder-Fixed Rod, Ring with fixed and movable hole

       - SUNDIALS ON VERTICAL CONE      -  EXTERNAL - INTERNAL SURFACE
         Fixed Cone-Fixed Rod, Fixed Cone-Movable Rod, Hat S., Shepherd's S.

       - TIME EQUATION Graphs ( 3 types )
     
    The Sundials can be calculated with or without Time-Equation

    In thi DEMO the Place's Latitude, Longitude and Time Zone cannot be
    changed.
   
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    INSTALLATION
    ============

    Copy the file SUNDEMO.ZIP on a DIR  and unzip the file ( using PKZIP)
    Start and run the program by entering: SUNDEMO

    The program runs under DOS  with EGA or VGA graphics and Dot-matrix
    (like EPSON) or Laser/InkJet (like HP) printers.
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    USING THE PROGRAMS
    =================

    All the programs have the same men and are very easy to use following
    the men options and the on-line help.
    With ESC-Key the programs always go back.
    In all programs are saved default data that can be used pressing ENTER 
    key.

    *************************************************************************
    * With the F1 key you can view a Help of several pages.                 *
    * Use this help for unusual Sundials as Cylindrical,Conical,Bifilar,etc.*
    *************************************************************************

    The following explanation refers  to PLANE SUNDIALS but is valid also for
    the others types.
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    SETUP

    In DEMO version :
      - Latitude, Longitude and Time-zone are fixed ;
      - Printing data and Hard-Copy are allowed, to test the printer, only
        in one program ( Conical Sundials )

    In the registered version the default data for the place (name, latitude,
    longitude,etc. ) and the type of video-card and printer can be changed
    and saved.
    The data pertinent the place can also be changed in the main program.
    ------------------------------------
  
    MAIN PROGRAM - AZIMUTH - ALTITUDE  (# 2 )

    To calculate the Sundial's points is necessary first to calculate the
    values of the Sun's Azimuth and Altitude : you can use the #2 choice or 
    <ENTER>.
    The program asks new values for place's name, latitude, longitude, Time
    -zone, starting and ending days of year, starting and ending hours of day.
    Press <ENTER> for default data.
   
    WITH Time Equation the Sundial's points are the TRUE shadows of projecting
    point G : every hour-line is looking an 8 (lemniscate curve).
    WITHOUT Time Equation the hour-lines are straight.

    The hour-lines will be calculated between starting and ending days.
    The interval between days is  a fixed number (integer) of days .
    You can also choose: the 1st day of every month,
                         the 1st and the 16th day of every month,
                         the 1st, the 11th and the 21th day of every month,
                         the days in which zodiacal-signs start.
    The maximum number of days is 75

    The daily-lines will be calculated between starting and ending hours.
    The interval between hours can be chosen from few minutes to several 
    hours.    
    The maximum number of points in a day is 24

    The values of Sun's Azimuth and Altitude (in the hours and in the days 
    choosen ) can be printed ( # 4 ) or saved on a file on the hard-disk 
    ( # 3 )
    ------------------------------------

    MAIN PROGRAM - SUNDIAL CALCULATION (# 6 )

    For the Sundial's plane you can choose :
        - the Inclination (angle between the Sundial's plane and the 
          horizontal one)          
        - the Azimuth (0 deg. if plane is facing South)
    After,  you can choose :
        - the Coordinate System ( on the Sundial's Plane or on the Horizontal)
        - the Coordinate's Type ( polar or rectangular: data are printed
          according to this coord.'s type)
        - the coordinates of point G casting the shadow (with several options).
      
    Sundial's data can be printed ( # 8 ) or saved on disk ( # 7 )
    ------------------------------------

    MAIN PROGRAM - Sundial DRAWING  (# 9 )

    On the screen are always plotted :
        - the hour-lines
        - the daily-lines on Solstices and on Spring's Equinox
        - the Coordinate's origin
        - the Meridian-line
        - the Sundial's center (where polar axis trough G intersects Sundial's
          plane)
        - the drawing's scale on the printer (left bottom corner)
        - the height of point G on the Sundial's plane (left upper corner)

     It's also possible to plot all the daily-lines.
   
      COMMANDS: Z - zoom
                A - anti-zoom
                Arrows - to move the picture on the screen
                # 0 , 1 , 2 , 3 - to plot the Sundial with a fixed scale
                                  on the printer
                S (shadow)      - to draw the shadow of the rod 
		PageUp/PageDown - to change the hour in the day ( the shadow 
                                  changes)
                Home/End        - to change the day in the year
                P   - the Sundial is drawn in perspective. 
                      The arrows now allow to change the point of view
                H   - hardcopy - The drawing is printed
                ESC - to return to the main Men
   
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    Ing. Gianni  Ferrari - Via Valdrighi 135 - 41100 Modena  -  ITALY
    EMail  :     frank.f@pianeta.it

