The planet Avalon is the fourth planet of the star known on Earth by a number of names, including β Canum Venaticorum, Asterion, Beta CVn, 8 CVn, BD +42 2321, FK5 470, HD 109358, HIP 61317, HR 4785, SAO 44230. But after the Fall, the only name anyone bothered with was Chara.
One of the most Earthlike of Earthlike planets, Avalon is a little larger than Earth and a little less dense. The surface gravity averages .95 G. Avalon's orbit is a little farther from Chara than Earth's from Sol, but Chara is a little brighter. The days on Avalon are a little longer, Lune is a little farther away than the moon, the continents drift a little slower, and the magnetic field surrounding the planet isn't quite as robust as Earth's, but still stronger than most.
Calendar Technicalities
Avalon becomes known by its inhabitants first as ‘Lon, and then simply Lon after the skin of the world breaks.
1 Lon year = 421.2 Lon days =1.265 Earth Years
1 Lon day = 26.3 Earth hours
A Lon Year has:
14 months of 30 days each, plus a bonus day in one Lon year. Every five years there is an extra bonus day. Bonus days do not have a day-name.
6 days in a "six" instead of "weeks" because it divides the month easily.
421.2 Lon days in a Lon year