Chapter 8 CHAPTER 8 Perl-fect Sundials John Redford This article describes a Perl 4 program for making sundials that can depict the cur- rent time to about a minute's accuracy. Typical sundials are only accurate to about half an hour, but the Perl sundials I'll describe correct for the latitude and longitude, and even for the eccentricity of the earth's orbit. To refresh your memory, sundials point to the current time with a shadow. In Figure 8-1 you can see the tip of the shadow of the gnomon--the upright part of a sundial--falling on a marking that indicates the time.