Sundial for Welkom

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.

       Welkom Area
        Time       Xtime       Ytime        date         Xan         Yan        Teqn       XTeqn
       05h00       2.374      -0.367       Jan01      -0.040       0.940      -15.00      -0.164
       05h30       2.456      -0.219       Jan15      -0.101       0.858      -10.00      -0.109
       06h00       2.496      -0.067       Feb01      -0.149       0.689       -5.00      -0.055
       06h30       2.493       0.087       Feb15      -0.154       0.506        0.00       0.000
       07h00       2.448       0.239       Mar01      -0.135       0.303        5.00       0.055
       07h30       2.360       0.387       Mar15      -0.099       0.093       10.00       0.109
       08h00       2.232       0.528       Apr01      -0.044      -0.166       15.00       0.164
       08h30       2.066       0.660       Apr15      -0.001      -0.370                        
       09h00       1.865       0.781       May01       0.033      -0.587                        
       09h30       1.632       0.889       May15       0.040      -0.748                        
       10h00       1.371       0.981       Jun01       0.025      -0.890                        
       10h30       1.086       1.057       Jun15      -0.004      -0.950                        
       11h00       0.783       1.114       Jul01      -0.039      -0.944                        
       11h30       0.466       1.152       Jul15      -0.065      -0.875                        
       12h00       0.142       1.171       Aug01      -0.067      -0.724                        
       12h30      -0.185       1.170       Aug15      -0.050      -0.548                        
       13h00      -0.509       1.148       Sep01       0.000      -0.330                        
       13h30      -0.824       1.107       Sep15       0.051      -0.127                        
       14h00      -1.125       1.047       Oct01       0.112       0.114                        
       14h30      -1.407       0.970       Oct15       0.154       0.321                        
       15h00      -1.665       0.875       Nov01       0.179       0.560                        
       15h30      -1.894       0.766       Nov15       0.169       0.731                        
       16h00      -2.091       0.643       Dec01       0.119       0.879                        
       16h30      -2.252       0.510       Dec15       0.055       0.948                        
       17h00      -2.374       0.367                  -0.040       0.940                        
       17h30      -2.456       0.219                                                            
       18h00      -2.496       0.067                                                            
       18h30      -2.493      -0.087                                                            
       19h00      -2.448      -0.239