) is a brilliant first-magnitude star
, believed to be the star that provided Hipparchus
with the data which enabled him to discover precession
of the equinoxes. The temple
was oriented with reference to Spica in about 3200 B.C
when it was constructed, and over time, precession resulted in a slow but noticeable change in the orientation of Earth
relative to Spica using the temple's fixed orientation and construction date to compare against. Nicolaus Copernicus
also made a lot of observations of Spica with his home-made triquetrum for his researches on precession.
The name Spica derives from the Latin spica, an ear of grain.
An easy way to find Spica is to follow the arc of the handle of the Big Dipper to Arcturus (α Bo÷tis), and then continue on the same distance to Spica.
Some facts about Spica
Spica is also the first Slovene astronomical magazine, edited by Bojan Kambič and published since 1995 (Slovene Spika).