SCDTL Calendar and Clock for Mars

Lance Latham
Resource Management Systems
120 Oakhaven Lane
Fredericksburg, TX 78624-4827

accepted for presention at
the Founding Convention of the Mars Society, August 13-16 1998,
University of Colorado, Boulder, Colorado, USA


The "Standard C Date/Time Library" (SCDTL), published by Miller Freeman, ISBN 0-879304-96-0, May 1998, is intended to be a standard reference in the area of computer date/time applications. The work is an integrated tool kit of data structures and functions in the "C" language, the "lingua franca" of today's machines. Comprising almost 4,200 pages, SCDTL addresses many areas, including some 30 different calendars.

The last is Martian.

The SCDTL Martian calendar is an annual solar calendar, in which the year is composed of equal 167-day quarters. Each quarter contains 3 months, configured as (56 + 56 + 55) days.

A simple leap year rule makes common years of years 2, 4, 6 and 8 of each 10 years, and makes an exception in the tenth year every 2000 years, yielding a calculated accuracy of one day in thirty-seven thousand years. The seven-day week is retained.

A linear time scale, called the Martian Day number (MD#), similar to the Julian Day number, is created for the Martian calendar, facilitating date and time calculations.

The SCDTL system also describes a clock for Mars, which uses the standard Terran second as its basis. The Martian clock day is defined as 25 hours of 53 minutes of 67 standard Terran seconds.

Compared to other proposed Martian calendars, the SCDTL calendar has numerous advantages. It is an integrated part of a huge, tested software application. Its design is based upon extensive experience with many calendars and a knowledge of those features which are psychologically and socially useful and successful, not merely technically feasible, or of interest to a handful of specialists.