Mystery Number on Drake Observatory

J. E. 6633.  What the heck does that mean?  It appears on the front of Drake Observatory and I'm pretty it's not a model number.  Hang on:  J. E. 6633 is a date based on the Julian Era, not the Julian Calendar. The Julian Era was invented by Joseph Scaliger in 1582 and named after his father, Julius Caesar Scaliger. Hence the Julian, hence the confusion with the Julian Calendar. The Era began on January 1, 4713 BCE according to the Julian Calendar. Baffled yet?  It gets odder. On that January 1, the 28-year solar cycle, the 19-year lunar cycle, and the 15-year indiction cycle (used in ancient Rome to regulate taxes) all began at once.  J. E. 6633 falls in 1920 on our Gregorian calendar. 1920 is the year construction began on the Observatory. There you go.

Sources:  Drake University Astronomy Professor Phillip Riggs, June 10 1971
The Julian Period. World Almanac & Book of Facts, 2009 as accessed through EBSCOhost
Photo courtesy Gerry Rowland