Eclipse Season Calendar

Courtesy of kjpargeter / Freepik

The Eclipse Season Calendar tracks the occurrence of the bifold eclipse seasons during which solar and lunar eclipses occur. Its year comprises 10 months of 34 or 35 days, two of which, Nyx and Nox, represent eclipse seasons. The length of the year varies between 346 and 348 days.

Month Layout

Name	Length in Days
Nyx	35
Moros	34
Ker	35
Thanatos	34 (35)
Hypnos	35
Nox	35
Momus	34
Nemesis	35
Apate	34 (35)
Eris	35

Intercalation

Odd-numbered years are common years of 346 days. Even-numbered years are leap years with an added 35 Thanatos. Years which are divisible by 8, but not 192 unless also divisible by 3840, are long years with both 35 Thanatos and an added 35 Apate. This scheme produces an average yearly duration of 346.62005 days, compared to the length of the actual eclipse year at 346.62010 days.

Epoch

The epochal date 1 Nyx 0 is equivalent to 19 February 1223 BCE. This date begins the eclipse season which contains the earliest recorded solar eclipse of 5 March 1223 BCE.

Examples

• The total solar eclipse that tracked across North America on 8 April 2024 occurred on 21 Nox 3420.
• The partial lunar eclipse occurring later that year takes place on 11 Nyx 3421, followed by an annular solar eclipse on 25 Nyx.
• Three eclipses take place during or adjacent to Nyx 3428, penumbral lunar on 7, annular solar on 21, and penumbral lunar on 1 Moros. Due to the intercalation cycle and fixed lengths of Nyx and Nox, some eclipses at the extreme end of a season may fall outside the designated month.