I suspect that the analemma, being familiar to the public on globes, sundials, etc., was used solely for that reason, call it artistic license.
Sun position lines (corresponding to the latitude dimension of an analemma) were marked on the floors of some cathedrals. See J. L. Heilbron's 1999 book "The sun in the church: cathedrals as solar observatories."
Prior to the availability of accurate clocks, the Equation of Time was determined by measuring the longitude of the sun. This was done by determining the position of the sun relative to the stars. Since the sun was observable only during the day, and the stars only at night, a mutually observable body was used to facilitate the measurement: the moon by the ancient astronomers and Venus by Tycho Brahe. The maximum 16-minute value of the Equation of Time corresponds to about 4 degrees of arc, so that observing instruments should be much more accurate than this.
Gordon Gordon Uber [EMAIL PROTECTED] San Diego, California USA Webmaster: Clocks and Time: http://www.ubr.com/clocks
