# Sundial for Richards Bay

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.
The units for the X and Y distances are metres for a walk-on sundial.
Note that the time- and datelines should be drawn as smooth curves.

```	Richards Bay
Time       Xtime       Ytime        date         Xan         Yan        Teqn       XTeqn
05h00       2.427      -0.289       Jan01      -0.040       0.933      -15.00      -0.164
05h30       2.484      -0.134       Jan15      -0.101       0.852      -10.00      -0.109
06h00       2.500       0.023       Feb01      -0.149       0.684       -5.00      -0.055
06h30       2.472       0.179       Feb15      -0.154       0.502        0.00       0.000
07h00       2.402       0.333       Mar01      -0.135       0.301        5.00       0.055
07h30       2.291       0.481       Mar15      -0.099       0.092       10.00       0.109
08h00       2.141       0.621       Apr01      -0.044      -0.165       15.00       0.164
08h30       1.954       0.750       Apr15      -0.001      -0.368
09h00       1.734       0.866       May01       0.033      -0.583
09h30       1.484       0.968       May15       0.040      -0.742
10h00       1.209       1.053       Jun01       0.025      -0.884
10h30       0.913       1.119       Jun15      -0.004      -0.943
11h00       0.601       1.167       Jul01      -0.039      -0.937
11h30       0.279       1.195       Jul15      -0.065      -0.869
12h00      -0.047       1.202       Aug01      -0.067      -0.719
12h30      -0.373       1.189       Aug15      -0.050      -0.544
13h00      -0.693       1.155       Sep01       0.000      -0.328
13h30      -1.000       1.102       Sep15       0.051      -0.126
14h00      -1.291       1.030       Oct01       0.112       0.113
14h30      -1.559       0.940       Oct15       0.154       0.318
15h00      -1.801       0.834       Nov01       0.179       0.556
15h30      -2.012       0.714       Nov15       0.169       0.725
16h00      -2.188       0.581       Dec01       0.119       0.873
16h30      -2.327       0.439       Dec15       0.055       0.941
17h00      -2.427       0.289                  -0.040       0.933
17h30      -2.484       0.134
18h00      -2.500      -0.023
18h30      -2.472      -0.179
19h00      -2.402      -0.333

```

since 2002/04/30
www.hartrao.ac.za/other/sundial/sdlrby.html
Last updated 2002/04/30 by M Gaylard