Spring Equinox

The Sun is one of those things we tend to take for granted. We might long for it during a blizzard, or curse it during a heat wave, but otherwise we pretty much ignore it. For much of human history, though, that was not the case — the Sun’s position played a key role in everything from agriculture to politics to religion.
The early Christian church, for example, needed a precise determination of the spring equinox to help set the date for Easter — a need that continued for centuries. During the 16th century, one astronomer tried to incorporate a solar marker in the design for Basilica Santa Maria in Florence. Known as a meridian line, it projected the Sun’s image onto the church floor. Seeing where the path overlapped in March and September would reveal the dates of the equinoxes.
The astronomer’s patron died before the project could be finished. But the spirit of his work is recalled in a meridian line at Austin College in Sherman, Texas. A solar viewing port in the wall of the colleg