In chronology, the solar equation necessary to prevent the new moon from happening a day too late, or the suppression of the bissextile once in 134 years. The opposite to this is the proemptosis, or the addition of a day every 300 years, and another every 2400 years.

The suppression of a day in the calendar to prevent the date of the new moon being set a day too late, or the suppression of the bissextile day once in 134 years. The opposite to this is the proemptosis, or the addition of a day every 330 years, and another every 2,400 years.