Sundial for Potchefstroom

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.

	Potchefstroom

        Time       Xtime       Ytime        date         Xan         Yan        Teqn       XTeqn
       05h00       2.380      -0.345       Jan01      -0.040       0.951      -15.00      -0.164
       05h30       2.459      -0.202       Jan15      -0.101       0.868      -10.00      -0.109
       06h00       2.497      -0.056       Feb01      -0.149       0.697       -5.00      -0.055
       06h30       2.492       0.092       Feb15      -0.154       0.511        0.00       0.000
       07h00       2.444       0.237       Mar01      -0.135       0.306        5.00       0.055
       07h30       2.354       0.379       Mar15      -0.099       0.094       10.00       0.109
       08h00       2.224       0.514       Apr01      -0.044      -0.168       15.00       0.164
       08h30       2.056       0.640       Apr15      -0.001      -0.375                        
       09h00       1.853       0.755       May01       0.033      -0.594                        
       09h30       1.618       0.858       May15       0.040      -0.756                        
       10h00       1.355       0.945       Jun01       0.025      -0.900                        
       10h30       1.070       1.017       Jun15      -0.004      -0.960                        
       11h00       0.766       1.071       Jul01      -0.039      -0.955                        
       11h30       0.448       1.107       Jul15      -0.065      -0.885                        
       12h00       0.124       1.124       Aug01      -0.067      -0.733                        
       12h30      -0.203       1.122       Aug15      -0.050      -0.554                        
       13h00      -0.527       1.100       Sep01       0.000      -0.334                        
       13h30      -0.841       1.060       Sep15       0.051      -0.128                        
       14h00      -1.141       1.001       Oct01       0.112       0.115                        
       14h30      -1.422       0.925       Oct15       0.154       0.324                        
       15h00      -1.678       0.834       Nov01       0.179       0.566                        
       15h30      -1.906       0.728       Nov15       0.169       0.739                        
       16h00      -2.101       0.610       Dec01       0.119       0.889                        
       16h30      -2.260       0.481       Dec15       0.055       0.958                        
       17h00      -2.380       0.345                  -0.040       0.951                        
       17h30      -2.459       0.202                                                            
       18h00      -2.497       0.056                                                            
       18h30      -2.492      -0.092                                                            
       19h00      -2.444      -0.237