Sundial

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Sundial (ver. 23.08)

Sundial is a simple program with a graphical interface for tracing a sundial for any location, on a plane with any orientation or inclination. The plot can include the stylus, the hourly lines, the monthly lines, the analemmas of mean solar time, and a Latin motto. The program uses the Dislin graphic library (https://www.dislin.de) for the graphical interface and plot.

Requisites

• Linux system,

• Dislin plotting library (https://www.dislin.de),

• Fortran 90 compiler (gfortran is assumed).

Distribution file

The distribution file sundial.tgz contains the following files:

• sundial.f90              (source file)

• dislin.mod               (dislin module)

•  sundial_help.txt         (help text file)

•  latin_english_mottos.txt (text file with the mottos in Latin and their translation)

•  sundial_lastpar.dat      (last parameters used)

Installing and running

Download the distribution file sundial.tgz  in the installation directory you like (for example $HOME/sundial), untar the file and compile the source file:

$ tar -xzvf sundial.tgz

$ gfortran sundial.f90 -o sundial -l dislin

The command 

$ sundial

opens a window displaying the current plot options, and an empty plot window (see below). 

To begin, press the "Redraw" button at the bottom of the window.

Plot options

Location

• N Latitude, positive Northward [degrees].

• E Longitude offset, positive Eastward [degrees] with respect to the central meridian of the time zone (it is only used for the plot of analemmas of solar mean time)

Orientation

Orientation of the outward perpendicular to the sundial plane.

• Direction (azimuth, from North to East) [degrees] 

• Inclination (altitude) [degrees] 

Examples: 

Direction Inclination

180       0          vertical sundial facing South

90        0          vertical sundial facing East

180       90         horizontal sundial

0         latitude   equatorial sundial, top face

180      -latitude   equatorial sundial, bottom face     

Stylus

Position of the stylus origin. The units are tenths of the sundial half-width.  

• X: rightward, horizontal, 

• Y: upward, maximum slope,

• Z: perpendicular to the sundial, useful for a stylus parallel to the sumdial

• Length of the stylus. 

Plot options

Selection of line style, line width or size, color, and background color for text

• Hourly lines: Plot of the hourly lines of apparent solar time that are visible on the sundial.

• Stylus: Plot of the stylus, put down on the sundial plane. The side where the plot is made is controlled by the sign of the style.

• Monthly lines: Plot of the monthly lines, indicated by the position of the stylus-tip shadow for each month, around day 20.

• Analemmas: Plot of the analemmas of solar mean time for every hour.

• Hour labels:: Plot of a label for every hour line.

• Latin motto: Plot of a Latin motto for the sundial.

Latin motto

A random list of Latin mottos is selected from the file latin_english_mottos.txt. 

• X,  Y: Position of the motto center, in units of tenths of the sundial half-width.

___________________________________________________________________

Line styles              Label styles    Colors

0: No line               0: No labels    0: White     8: Orange

1: Solid       ________  1: Arabic 0-24  1: Black     9: LightGreen

2: Dotted      ........  2: Roman I-XII  2: Red      10: DarkRed

3: Dashed      _ _ _ _                   3: Green    11: DarkGreen

4: LongMedDash ___ __                    4: Blue     12: DarkBlue

5: DotDash     ._._._._                  5: Cyan     13: Pink

6: MedDash     __ __ __                  6: Magenta  14: Brown

7: LongDot     . . . .                   7: Yellow   15: Gray

8: LongDash    ___ ___