Epacts

If, then, the new moon occurs on 1 January in the first year of the Lunar Cycle, the Epact of the year is or, as it is more usually expressed, *; and since the lunar year always begins with the new moon, it is clear that the divergence between the solar and lunar calendars, of which we have just been speaking, gives the Epacts of the succeeding years.

The Catholic Encyclopedia, Volume 5: Diocese-Fathers of Mercy 1840-1916 1913

But we have shown that when the solar and lunar years begin on the same day, the Epacts of the successive years of the cycle are:

The Catholic Encyclopedia, Volume 5: Diocese-Fathers of Mercy 1840-1916 1913

Epacts was supported by Alexander Piccolomini, coadjutor Bishop of

The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy 1840-1916 1913

According to the Metonic Cycle, the new moon can never occur twice on the same date in the same nineteen years (the case is exceedingly rare even in the purely astronomical calendar); consequently, whenever the two Epacts XXV and XXIV occur in the same nineteen years, the new moons of the year whose Epact is

The Catholic Encyclopedia, Volume 5: Diocese-Fathers of Mercy 1840-1916 1913

These astronomers having drawn up the table of equations to show the changes in the Epacts necessary to preserve the relations between the ecclesiastical and astronomical calendars, proceeded to calculate the proper Epacts for the years of the Lunar Cycle after 1582.

The Catholic Encyclopedia, Volume 5: Diocese-Fathers of Mercy 1840-1916 1913

Mondovi, declared itself against astronomical lunations and for the cycle of Epacts.

The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy 1840-1916 1913

Lilius brought the new cycle of Epacts in harmony with the year by two equations so called, the solar and the lunar.

The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy 1840-1916 1913

Lilius's masterpiece is the new "Nineteen Years 'Cycle of Epacts", by which he kept the Nicæan Easter regulation apace with the astronomical moon.

The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy 1840-1916 1913

It was probably owing to his objections that the new cycle of Epacts was changed at least twice and recommended by the commission in a third or even later form.

The Catholic Encyclopedia, Volume 9: Laprade-Mass Liturgy 1840-1916 1913

This addition of one to the Epacts is known as the Lunar Equation, and occurs at the beginning of the years 1800, 2100, 2400, 2700, 3000, 3300, 3600,

The Catholic Encyclopedia, Volume 5: Diocese-Fathers of Mercy 1840-1916 1913