Solar Calendar with Lunar Months

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Solar Calendar with Lunar Months

Walter J Ziobro
SOLAR CALENDAR WITH LUNAR MONTHS

This calendar is a 365/366 day calendar with 12 and 1/3 months.  Although it will commence each year with a different lunar age, every subsequent month of a given year will show the same age of the moon on the same monthly date.   One can calculate the age of the moon on any given date by adding the Gregorian epact for the year to the month date, and subtracting 30 if the result exceeds 30:

Month name        Days in each month            Gregorian start date

Protosel         30                     Jan 01
Deutersel         29 (30 in leap years)             Jan 31
Trisel             30                     Mar 01
Tetrasel         29                     Mar 31
Pentasel         30                     Apr 29
Hexasel         29                     May 29
Heptasel         30                     Jun 27
Oktasel             29                     Jul 27
Enasel             30                     Aug 25
Dekasel         29                     Sep 24
Hendesel         30                     Oct 23
Dodekasel         29                     Nov 22
Tridekasel         11                     Dec 21

The month names are derived from Greek numerals with the suffix -sel, from the Greek word for the moon: Selene.

-Walter Ziobro
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Re: Solar Calendar with Lunar Months

Karl Palmen

Dear Walter and Calendar People

 

I have previously suggested such a calendar with the new year about 5 or 6 days after the June solstice so that the other solstice and equinoxes occur very near the start of the month.

 

This suggestion has two months begin at the same time as a Gregorian month (Protosel-January & Trisel-March).  

 

The 13th month of 11 days is a little more than a 1/3 of a month, so I would not regard such a calendar as having 12 1/3 months, but as having 12 months and 11 days. This has made me think of a similar calendar that runs on the 3-year cycle of 37 months. The first 12 months of each year alternate between 29 and 30 days not counting leap days and every 3rd year has a leap month of 33 days. The moon phases would then be revised once every 3 years after the 33-day leap month.

 

I think the Roman calendar may have been intended to run on a 2-year cycle with a leap month every other year of 22 days with a leap day added to every other leap month bring it up to 23 days.

 

Karl

 

16(08(01

 

Tuesday King of Clubs – ISO deck

 

From: East Carolina University Calendar discussion List [mailto:[hidden email]] On Behalf Of Walter J Ziobro
Sent: 28 March 2017 15:11
To: [hidden email]
Subject: Solar Calendar with Lunar Months

 

SOLAR CALENDAR WITH LUNAR MONTHS

This calendar is a 365/366 day calendar with 12 and 1/3 months.  Although it will commence each year with a different lunar age, every subsequent month of a given year will show the same age of the moon on the same monthly date.   One can calculate the age of the moon on any given date by adding the Gregorian epact for the year to the month date, and subtracting 30 if the result exceeds 30:

Month name        Days in each month            Gregorian start date

Protosel                        30                                             Jan 01
Deutersel          29 (30 in leap years)                  Jan 31
Trisel                            30                                             Mar 01
Tetrasel                         29                                             Mar 31
Pentasel                       30                                             Apr 29
Hexasel                        29                                             May 29
Heptasel                       30                                             Jun 27
Oktasel                         29                                             Jul 27
Enasel                          30                                             Aug 25
Dekasel                        29                                             Sep 24
Hendesel                      30                                             Oct 23
Dodekasel                                29                                             Nov 22
Tridekasel                     11                                             Dec 21

The month names are derived from Greek numerals with the suffix -sel, from the Greek word for the moon: Selene.

-Walter Ziobro