Sundial for Gauteng

Note that the "squares" on the diagram must look square, ie one unit of length horizontally must equal one unit of length vertically.

The data used to create this sundial are listed below, if you want to make your own large "walk-on" sundial. The columns are:

• Time: time at each marker on the timeline.
• Xtime: X (horizontal) offset from 0.0 (centre of graph) of each time marker.
• Ytime: Y (vertical) offset from 0.0 (centre of graph) of each time marker.
• Date: Date of each marker on the date line and analemma ("8")
• Xan: X (horizontal) offset from 0.0 (centre of graph) of each date marker on the analemma.
• Yan: Y (vertical) offset from 0.0 (centre of graph) of each date marker on the analemma; this is equal to the Y offset for the dateline. The X values for the dateline are 0.0.
• Teqn: The offsets of time correction scale at the foot of the analemma, in minutes. -15 means the Sun is 15 minutes late (e.g. in February), so 15 minutes must be added to the time read from the shadow crossing the timeline when standing on the dateline. +15 means the Sun is 15 minutes early (e.g. in early November), so 15 minutes must be subtracted from the time read from the shadow crossing the timeline when standing on the dateline.
• XTeqn: X (horizontal) offset from 0.0 of the time correction at the foot of the analemma. The Y value is set to place it conveniently below the analemma.

       Gauteng: set for Midrand, but good for Pretoria and Johannesburg

 Time       Xtime       Ytime        date         Xan         Yan        Teqn       XTeqn
05h00       2.391      -0.320       Jan01      -0.040       0.957      -15.00      -0.164
05h30       2.466      -0.181       Jan15      -0.101       0.873      -10.00      -0.109
06h00       2.498      -0.038       Feb01      -0.149       0.701       -5.00      -0.055
06h30       2.488       0.105       Feb15      -0.154       0.515        0.00       0.000
07h00       2.436       0.247       Mar01      -0.135       0.308        5.00       0.055
07h30       2.342       0.384       Mar15      -0.099       0.094       10.00       0.109
08h00       2.207       0.515       Apr01      -0.044      -0.169       15.00       0.164
08h30       2.035       0.636       Apr15      -0.001      -0.377                        
09h00       1.828       0.747       May01       0.033      -0.598                        
09h30       1.590       0.846       May15       0.040      -0.761                        
10h00       1.325       0.929       Jun01       0.025      -0.906                        
10h30       1.037       0.997       Jun15      -0.004      -0.967                        
11h00       0.731       1.048       Jul01      -0.039      -0.961                        
11h30       0.413       1.081       Jul15      -0.065      -0.891                        
12h00       0.087       1.095       Aug01      -0.067      -0.737                        
12h30      -0.240       1.091       Aug15      -0.050      -0.558                        
13h00      -0.562       1.068       Sep01       0.000      -0.336                        
13h30      -0.876       1.027       Sep15       0.051      -0.129                        
14h00      -1.174       0.968       Oct01       0.112       0.116                        
14h30      -1.452       0.892       Oct15       0.154       0.326                        
15h00      -1.705       0.802       Nov01       0.179       0.570                        
15h30      -1.929       0.697       Nov15       0.169       0.744                        
16h00      -2.120       0.581       Dec01       0.119       0.895                        
16h30      -2.275       0.454       Dec15       0.055       0.964                        
17h00      -2.391       0.320                  -0.040       0.957                        
17h30      -2.466       0.181                                                            
18h00      -2.498       0.038                                                            
18h30      -2.488      -0.105                                                            
19h00      -2.436      -0.247