When the web page is loaded the ephemeris calculator automatically selects the epoch date for the tables in Ptolemy’s Almagest as the default date. This corresponds with mean noon at the meridian of Alexandria on 1 Thoth 1 Nabonassar (or 26 February 747 BC in the proleptic Julian calendar, around 10h UT).
You will certainly remember that 747 BC is at or about the time that Sargon II conquered the Hittites. Remember? And then they came out with that lame sitcom about it, Sargon’s Heroes? I’m sure you remember.