The Douglass-Pickering Calendar at a Glance

Year Published c. 1900
Days per Week 7
Days per Month 55-56
Months per Year 12
Base Year Length 668
Leap Days 1
Leap Day Position end of year
Basic Intercalation Formula 2x668 + 3x669
Extended Intercalation Formula
(\ denotes integer division)
Y\5 + (Y-2)\5 + (Y-3)\5
Mean Length of Calendar Year 668.6
Base Astronomical Year Vernal Equinox
Accuracy 145 years
Cycle of Perpetuity none
Mean LS of Beginning of Year 0.0
Year Count Start undefined
Epoch (CE) undefined
Epoch (JD) undefined
12-Month Naming Convention Anglicized Roman Days
1st Month March 56
2nd Month April 56
3rd Month May 56
4th Month June 56
5th Month July 56
6th Month August 56
7th Month September 56
8th Month October 56
9th Month November 55
10th Month December 55
11th Month January 55
12th Month February 55-56
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 Symmetric Gregorian Martian calendars, which generally have the following characteristics:

  2. Other types of 12-month calendars are:

Document i brani da Il Pianeta Marte
Mentore Maggini
Document excerpts from The Planet Mars
Mentore Maggini
Calendar Calendar
Martian Time

Martian Time

Martian Time Survey

Martian Time Survey 2.2