The Briggs-Houben CMEX Calendar at a Glance

Year Published 1997
Days per Week 7
Days per Month 42-70
Months per Year 12
Base Year Length 665
Leap Days 7
Leap Day Position end of 8th month (of 12)
Basic Intercalation Formula 49x665 + 51x672
Extended Intercalation Formula
(\ denotes integer division)
Y\2 + (Y-1)\100
Mean Length of Calendar Year 668.5700
Base Astronomical Year Winter Solstice
Accuracy 38 years
Cycle of Perpetuity 1 year
Mean LS of Beginning of Year 264-268
Year Count Start 1
Epoch (CE) 1975 Jul 7
Epoch (JD) 2442601
12-Month Naming Convention Anglicized Roman truncated + "Ar" Days
1st Month Arjan 49
2nd Month Arfeb 49
3rd Month Armar 56
4th Month Arear 63
5th Month Armay 63
6th Month Arjun 70
7th Month Arjul 63
8th Month Araug 56-63
9th Month Arsep 56
10th Month Aroct 49
11th Month Arnov 49
12th Month Ardec 42
7-day Naming Convention English
1st Day Sunday
2nd Day Monday
3rd Day Tuesday
4th Day Wednesday
5th Day Thursday
6th Day Friday
7th Day Saturday

Notes:

  1. This is one of several Asymmetric Gregorian Martian calendars, which generally have the following characteristics:

  2. Other types of 12-month calendars are:

Document Martian Timekeeping
Geoffrey Briggs and Howard Houben
Calendar Calendar
Martian Time

Martian Time

Martian Time Survey

Martian Time Survey 2.2