# Tabula Noviluniorum

In the city of Rome, 1588, Christopher Clavius published a table of ecclesiastical new moons in his book NOVI CALENDARII ROMANI APOLOGIA​. The rows contained all possible Gregorian epacts, while the columns displayed all of the months of the year. At each intersection one could determine the month and date where the new moon was to occur for each given epact. Of particular note was the fact that there could be up to two new moons, while in other months, such as the month of February (epact 0) there would be no new moon. As opposed to the original table used prior to this publication, there are two differences: rows with the normal epact of 25 and the special epact of 25 (i.e. Golden number greater than 11, where the ecclesiastical full moon was formerly situated) are swapped. Another change is at the intersection of the Special Epact 25 row and the July column. Here, the numbers 2 and 31 are inserted into this cell, because this epact is also written on 31 July in the original Calendarium Gregorianum table (alongside epact 26). Surprisingly, there is only the epact number 2 in the original table, so one new moon simply fell off.

Important to note are the newer new moons for the days 8 to 31, and the April new moons for days 1 to 5, which are highlighted. 13 days after these new moons, an ecclesiastical full moon occurs (i.e. between 21 March and 18 April), with the next Sunday after this full moon being Easter Sunday.

Instructions for use:

• Find the Gregorian epact for a given year (e.g. by using the page Chronological Cycles).
• In the line with the epact, all cyclic new moons in a given year are listed.
• If a given year has a Gregorian epact of 19 and at the same time a golden number of 19, add the new moon of 31 December that is in parentheses. For an explanation of why this is the case, see the Calendarium Gregorianum table page in the second to last paragraph.

For example, 2015 has an epact of 10, the first ecclesiastical new moon of the year is 21 January (technically, 20 January), followed by 19 February (this is precise), and so on until the last ecclesiastical new moon of 2015 on 11 December (again, precisely). Actual and ecclesiastical new moons can vary by up to two days.

EpactJanFebMarAprMayJunJulAugSepOctNovDec
01,311,31292927272524232221
292121,303028282625242322
2832321,3129292726252423
27434321,30302827262524
265454321,312928272625
256464422,313028282626
2565654321,3029282726
2475755331,3129292727
23868664421,30302828
229797755321,312929
211081088664321,3030
2011911997754321,31
1912101210108865432,(31)
1813111311119976543
171412141212101087654
161513151313111198765
1516141614141212109876
14171517151513131110987
131816181616141412111098
1219171917171515131211109
11201820181816161413121110
10211921191917171514131211
9222022202018181615141312
8232123212119191716151413
7242224222220201817161514
6252325232321211918171615
5262426242422222019181716
4272527252523232120191817
3282628262624242221201918
2292729272725252322212019
1302830282826262423222120