  Earth's analemma is the lopsided figure eight marked out over a year by the
position of the Sun in the sky observed at the same clock time each day. It
shows how solar time deviates from clock time. The analemma's shape results
from the tilt of Earth's axis of rotation relative to the plane of its orbit
around the Sun and from the elliptical shape of that orbit. This tutorial paper
uses vector analysis of the Earth-Sun geometry and a numerically generated
quantitative description of Earth's motion around the Sun to construct Earth's
analemma. To visualize the geometry and the motion that give rise to the
analemma is challenging, but this construction is a project within the
capability of physics students who have had basic undergraduate mechanics.
