The 72-inch Armillary Sphere has one large vertical ring representing the meridian of Houston. Attached to the inside of this ring is a wide band decorated with the signs of the zodiac and representing the celestial equator. Slanting up through the middle is a rod with a ball at its upper end representing the earth’s axis. Armillary Sphere is so designed that this central rod points toward the North Pole of the heavens, very close to the North Star. As the sun moves across the heavens from east to west in the course of a day, the shadow of the central rod moves across the inside of the equatorial band, passing from one hour to another, and showing constantly the actual sun time in Houston. This Armillary Sphere has been carefully designed for its precise location, and thus shows the actual sun time. It was donated to the City of Houston in 1977 by then-President of the Houston Heritage Society, Elizabeth Bracewell.