preface computation of flat sundials. fer j. de vries
preface In these pages you find the basic procedures to compute all kinds of lines
for a flat sundial.
The procedures form a suitable basis for computer
programs.
The definitions have been formulated so that the method is
uniform in all situations, for both the northern and southern hemispheres and
for any plane, no matter what its orientation.
The principle of a sundial is to convert a certain sun's position into
coordinates for a shadow point on the dial's face. An uniform main procedure
does this job.
Secondary procedures are used to find a number of points for
any line you want to calculate.
All the drawings and pictures of sundials on these pages are computed with these procedures.
