created by Carl Sabanski
"Dialling Guides" - Horizontal & Vertical Sundials
The purpose of the "Dialling Guides" is to provide an easy method for laying out the hour lines for a number of horizontal and vertical sundials located at various latitudes in either the Northern or Southern Hemispheres. Figure 1 is an illustration of a typical "Dialling Guide". It is designed to show local apparent or solar time.
Figure 1: "Dialling Guide" (ZW2000/CAD)
There are a total of 81 "Dialling Guides" that cover the range of latitudes from 25° to 65° inclusive in increments of 0.5°. Each "Dialling Guide" illustrates how to lay out the hour lines for the following sundials in minimum time increments of 5 minutes:
Horizontal Sundial - Northern Hemisphere
The sundials are numbered on the "Dialling Guides" as indicated above. For any given latitude the "Dialling Guides" can be used to design the following sundials:
In order to design these three sundials for a given latitude, two "Dialling Guides" must be obtained. The "Dialling Guide" for the desired latitude is required for the horizontal sundial and one for the co-latitude is required for the vertical direct south and north sundials. This is easy to do. Just find a "Dialling Guide" close to your latitude in the following table and you will have one of your "Dialling Guides". The one for your co-latitude is on the same line. Don't forget the instructions.
To assist you in visualizing the hour limits imposed
on each of the sundials you should make a "Dialling Buddy" or
obtain a set of "Sun Charts" for your latitude. It is amazing
what you will learn from either of these, particularly if you are new to
dialling. It is worth the effort!
If you see what might be a problem with any of the "Dialling Guides" please let me know. Thank you.
If you are interested in a custom "Dialling Guide" designed for your particular location or one that has the hour lines corrected for longitude, we can help you.