# Are there any non-lunar, non-solar calendars? **URL:** \ **Category:** Factual Questions\ **Created:** [November 27, 2009, 7:50pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165 "2009-11-27T19:50:15Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![katie9264](https://avatars.discourse-cdn.com/v4/letter/k/df788c/32.png) [@katie9264](https://boards.straightdope.com/u/katie9264)\ **Post date:** [November 27, 2009, 7:50pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/1 "2009-11-27T19:50:15Z")
I am looking into adopting an alternative calendar system for personal use. Preferably, one that would be as eccentric as possible, but have been in used in some real capacity in the past. Which leads me to ask: It seems that almost all calendar systems are either solar, lunar or lunisolar. Are there any fully documented calendar systems that exist outside of these realms? ---
**Author:** ![fandango](https://avatars.discourse-cdn.com/v4/letter/f/b5ac83/32.png) [@fandango](https://boards.straightdope.com/u/fandango)\ **Post date:** [November 27, 2009, 8:04pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/2 "2009-11-27T20:04:12Z")
Use the one that Unix uses which just counts the milliseconds since an arbitrary date in the 1970s ---
**Author:** ![whitetho](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whitetho/32/1059_2.png) [@whitetho](https://boards.straightdope.com/u/whitetho)\ **Post date:** [November 27, 2009, 8:10pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/3 "2009-11-27T20:10:42Z")
Another option from an even more obscure programming language: [MUMPS](http://en.wikipedia.org/wiki/MUMPS) > [@](#): > > In MUMPS, the current date and time is contained in a special system variable, $H (short for “HOROLOG”). The format is a pair of integers separated by a comma, e.g. “54321,12345” The first number is the number of days since December 31, 1840, i.e. day number 1 is January 1, 1841; the second is the number of seconds since midnight. ---
**Author:** ![pravnik](https://avatars.discourse-cdn.com/v4/letter/p/8edcca/32.png) [@pravnik](https://boards.straightdope.com/u/pravnik)\ **Post date:** [November 27, 2009, 8:13pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/4 "2009-11-27T20:13:18Z")
The ancient Egyptians had a 365 day calandar that wasn’t exactly solar. It was based on the rise of Sirius and the yearly Nile flood. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [November 27, 2009, 8:20pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/5 "2009-11-27T20:20:04Z")
[Julian Day](http://en.wikipedia.org/wiki/Julian_day). ---
**Author:** ![katie9264](https://avatars.discourse-cdn.com/v4/letter/k/df788c/32.png) [@katie9264](https://boards.straightdope.com/u/katie9264)\ **Post date:** [November 27, 2009, 8:20pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/6 "2009-11-27T20:20:55Z")
Interesting, but I guess I am looking for a system that is a little more fleshed out, with specific divisions. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [November 27, 2009, 8:25pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/7 "2009-11-27T20:25:36Z")
How about the Aztec [tonalpohualli](http://en.wikipedia.org/wiki/Tonalpohualli)? It’s a 260-day calendar. It’s not clear at this point exactly what it was based on. But it doesn’t line up with the year, so it’s not solar. It was divided into 20 periods of 13 days each, which isn’t lunar. I’ve found [an online Aztec calendar converter](http://www.azteccalendar.com/calendar-calculator.html) that you could use. ---
**Author:** ![Bytegeist](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)\ **Post date:** [November 27, 2009, 8:40pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/8 "2009-11-27T20:40:14Z")
> [@katie9264](#): > > Are there any non-lunar, non-solar calendars? You could always try to revive the [French Republican Calendar](http://en.wikipedia.org/wiki/French_Republican_Calendar). Maybe it’ll catch on this time. It is still “solar” however in that it tracks years, like the Gregorian. > [@fandango](#): > > Use the one that Unix uses which just counts the milliseconds since an arbitrary date in the 1970s. The “arbitrary” date is not so arbitrary: it’s January 1, 1970. Also, the unit used is normally seconds. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [November 27, 2009, 10:05pm UTC](https://boards.straightdope.com/t/are-there-any-non-lunar-non-solar-calendars/519165/9 "2009-11-27T22:05:23Z")
IIRC, the Aztex? Myans? somebodies had a calender based upon the movements of Venus. It was pretty damn long and complicated and IMO quite sophisticated too. Once hearing about it, you realized these guys had to have been taking detailed notes and thinking about this for probably centuries to even come up with it.