Sundial for Windhoek, Namibia

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.

       Windhoek, Namibia
        Time       Xtime       Ytime        date         Xan         Yan        Teqn       XTeqn
       05h00       2.207      -0.449       Jan01      -0.040       0.984      -15.00      -0.164
       05h30       2.342      -0.335       Jan15      -0.101       0.898      -10.00      -0.109
       06h00       2.436      -0.215       Feb01      -0.149       0.721       -5.00      -0.055
       06h30       2.488      -0.092       Feb15      -0.154       0.529        0.00       0.000
       07h00       2.498       0.033       Mar01      -0.135       0.317        5.00       0.055
       07h30       2.466       0.158       Mar15      -0.099       0.097       10.00       0.109
       08h00       2.391       0.280       Apr01      -0.044      -0.174       15.00       0.164
       08h30       2.275       0.397       Apr15      -0.001      -0.388                        
       09h00       2.120       0.507       May01       0.033      -0.615                        
       09h30       1.929       0.609       May15       0.040      -0.782                        
       10h00       1.705       0.700       Jun01       0.025      -0.932                        
       10h30       1.452       0.779       Jun15      -0.004      -0.994                        
       11h00       1.174       0.845       Jul01      -0.039      -0.988                        
       11h30       0.876       0.896       Jul15      -0.065      -0.916                        
       12h00       0.562       0.932       Aug01      -0.067      -0.758                        
       12h30       0.240       0.952       Aug15      -0.050      -0.573                        
       13h00      -0.087       0.956       Sep01       0.000      -0.345                        
       13h30      -0.413       0.944       Sep15       0.051      -0.133                        
       14h00      -0.731       0.915       Oct01       0.112       0.119                        
       14h30      -1.037       0.871       Oct15       0.154       0.336                        
       15h00      -1.325       0.811       Nov01       0.179       0.586                        
       15h30      -1.590       0.738       Nov15       0.169       0.764                        
       16h00      -1.828       0.652       Dec01       0.119       0.920                        
       16h30      -2.035       0.556       Dec15       0.055       0.991                        
       17h00      -2.207       0.449                  -0.040       0.984                        
       17h30      -2.342       0.335                                                            
       18h00      -2.436       0.215                                                            
       18h30      -2.488       0.092                                                            
       19h00      -2.498      -0.033                                                            

Note that no allowance is made for daylight saving time.