Editing Month (section)

===Old Celtic calendar===
The [[Coligny calendar]] (Gaulish/Celtic) is an Iron Age Metonic lunisolar calendar, with 12&nbsp;lunar months of either 29 or 30&nbsp;days. The lunar month is calculated to a precision of within 24&nbsp;hours of the lunar phase, achieved by a particular arrangement of months, and the month of EQUOS having a variable length of 29 or 30&nbsp;days to adjust for any lunar slippage.  This setup means the calendar could stay precisely aligned to its lunar phase indefinitely. 

The lunar month is divided into two halves, the first of 15&nbsp;days and the second of 14 or 15&nbsp;days. The month is calculated to start at the first quarter moon, with the full moon at the centre of the first half-month and the dark moon at the centre of the second half-month.  The calendar does not rely on unreliable visual sightings.

An intercalary lunar month is inserted before every 30&nbsp;lunar months to keep in sync with the solar year. Every 276&nbsp;years this adds one day to the solar point, so if for example the calendar was 1,000&nbsp;years old, it would only have slipped by less than 4&nbsp;days against the solar year. 

{| class="wikitable" style="text-align: center"
|-
! scope="col" |  !! scope="col" | Name 
! width=60px | Days !! scope="col" | Meaning
! width=150px| Modern months
|-
| {{math|I}}-1 || Unknown || 30 ||  || Intercalary One
|-
| 1 || {{lang|xtg|Samonios}} || 30 || summer month || May-June
|-
| 2 || {{lang|xtg|Dumannios}} || 29 ||  || June-July
|-
| 3 || {{lang|xtg|Rivros}} || 30 || fat month  || July-August
|-
| 4 || {{lang|xtg|Anagantios}} || 29 || || August-September
|-
| 5 || {{lang|xtg|Ogronios}} || 30 || cold month || September-October
|-
| 6 || {{lang|xtg|Cutios}}    || 30 || wind month || October-November
|-
| {{math|I}}-2 || {{lang|xtg|[.]antaran[...]}}|| 30 ||  || Intercalary Two
|-
| 7 || {{lang|xtg|Giamonios}} || 29 || winter month || November-December
|-
| 8 || {{lang|xtg|Simivisonnios}} || 30 ||  || December-January
|-
| 9 || {{lang|xtg|Equos}}   || 29 or 30 || || January-February
|-
| 10 || {{lang|xtg|Elembivios}} || 29 ||  || February-March
|-
| 11 || {{lang|xtg|Edrinios}}  || 30 || month of heat || March-April
|-
| 12 || {{lang|xtg|Cantlos}} || 29 || month of song|| April-May
|-
|}