Module calendrica-astronomical-lunar
Astronomical lunar calendar conversions (Babylonian, Observational Islamic/Hebrew, Samaritan).
Ported from "Calendrical Calculations" (4th edition) by Nachum Dershowitz and Edward M. Reingold. Original Lisp code (CALENDRICA 4.0) is Apache 2.0 licensed.
Info:
- Release: 0.1 2026-07-19
Functions
| fixed_from_babylonian (b_date) | Fixed date equivalent to Babylonian date `b_date`. |
| babylonian_from_fixed (date) | Babylonian date {year, month, leap, day} corresponding to fixed `date`. |
| fixed_from_observational_islamic (i_date) | Fixed date equivalent to Observational Islamic date `i_date`. |
| observational_islamic_from_fixed (date) | Observational Islamic date {year, month, day} corresponding to fixed `date`. |
| fixed_from_saudi_islamic (s_date) | Fixed date equivalent to Saudi Islamic date `s_date`. |
| saudi_islamic_from_fixed (date) | Saudi Islamic date {year, month, day} corresponding to fixed `date`. |
| fixed_from_turkish_islamic (i_date) | Fixed date equivalent to Turkish Islamic date `i_date`. |
| turkish_islamic_from_fixed (date) | Turkish Islamic date {year, month, day} corresponding to fixed `date`. |
| fixed_from_astronomical_islamic_umalqura (i_date) | Fixed date equivalent to astronomical Umm al-Qura date `i_date`. |
| astronomical_islamic_umalqura_from_fixed (date) | Astronomical Umm al-Qura date {year, month, day} corresponding to fixed `date`. |
| astronomical_easter (g_year) | Date of (proposed) astronomical Easter in Gregorian year `g_year`. |
| fixed_from_observational_hebrew (h_date) | Fixed date equivalent to Observational Hebrew date `h_date`. |
| observational_hebrew_from_fixed (date) | Observational Hebrew date {year, month, day} corresponding to fixed `date`. |
| samaritan_from_fixed (date) | Samaritan date {year, month, day} corresponding to fixed `date`. |
| fixed_from_samaritan (s_date) | Fixed date of Samaritan date `s_date`. |
| babylonian_leap_year (b_year) | True if Babylonian year `b_year` is a leap year. |
| phasis_on_or_before (date, location) | Closest fixed date on or before `date` when crescent moon first became visible at `location`. |
| phasis_on_or_after (date, location) | Closest fixed date on or after `date` when crescent moon first became visible at `location`. |
| shaukat_criterion (date, location) | True if crescent moon is likely visible on the eve of `date` at `location` (Shaukat criterion). |
| yallop_criterion (date, location) | True if crescent moon is possibly visible on the eve of `date` at `location` (Yallop criterion). |
Functions
- fixed_from_babylonian (b_date)
-
Fixed date equivalent to Babylonian date `b_date`.
Parameters:
- b_date table Babylonian date {year, month, leap, day}.
Returns:
-
number
Fixed date.
- babylonian_from_fixed (date)
-
Babylonian date {year, month, leap, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, leap, day}
- fixed_from_observational_islamic (i_date)
-
Fixed date equivalent to Observational Islamic date `i_date`.
Parameters:
- i_date table Islamic date {year, month, day}.
Returns:
-
number
Fixed date.
- observational_islamic_from_fixed (date)
-
Observational Islamic date {year, month, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- fixed_from_saudi_islamic (s_date)
-
Fixed date equivalent to Saudi Islamic date `s_date`.
Parameters:
- s_date table Islamic date {year, month, day}.
Returns:
-
number
Fixed date.
- saudi_islamic_from_fixed (date)
-
Saudi Islamic date {year, month, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- fixed_from_turkish_islamic (i_date)
-
Fixed date equivalent to Turkish Islamic date `i_date`.
Parameters:
- i_date table Islamic date {year, month, day}.
Returns:
-
number
Fixed date.
- turkish_islamic_from_fixed (date)
-
Turkish Islamic date {year, month, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- fixed_from_astronomical_islamic_umalqura (i_date)
-
Fixed date equivalent to astronomical Umm al-Qura date `i_date`.
Parameters:
- i_date table Islamic date {year, month, day}.
Returns:
-
number
Fixed date.
- astronomical_islamic_umalqura_from_fixed (date)
-
Astronomical Umm al-Qura date {year, month, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- astronomical_easter (g_year)
-
Date of (proposed) astronomical Easter in Gregorian year `g_year`.
Parameters:
- g_year number Gregorian year.
Returns:
-
number
Fixed date.
- fixed_from_observational_hebrew (h_date)
-
Fixed date equivalent to Observational Hebrew date `h_date`.
Parameters:
- h_date table Hebrew date {year, month, day}.
Returns:
-
number
Fixed date.
- observational_hebrew_from_fixed (date)
-
Observational Hebrew date {year, month, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- samaritan_from_fixed (date)
-
Samaritan date {year, month, day} corresponding to fixed `date`.
Parameters:
- date number Fixed date.
Returns:
-
table
{year, month, day}
- fixed_from_samaritan (s_date)
-
Fixed date of Samaritan date `s_date`.
Parameters:
- s_date table Samaritan date {year, month, day}.
Returns:
-
number
Fixed date.
- babylonian_leap_year (b_year)
-
True if Babylonian year `b_year` is a leap year.
Parameters:
- b_year number Babylonian year.
Returns:
-
boolean
- phasis_on_or_before (date, location)
-
Closest fixed date on or before `date` when crescent moon first became visible at `location`.
Parameters:
- date number Fixed date.
- location table Location table.
Returns:
-
number
Fixed date.
- phasis_on_or_after (date, location)
-
Closest fixed date on or after `date` when crescent moon first became visible at `location`.
Parameters:
- date number Fixed date.
- location table Location table.
Returns:
-
number
Fixed date.
- shaukat_criterion (date, location)
-
True if crescent moon is likely visible on the eve of `date` at `location` (Shaukat criterion).
Parameters:
- date number Fixed date.
- location table Location table.
Returns:
-
boolean
- yallop_criterion (date, location)
-
True if crescent moon is possibly visible on the eve of `date` at `location` (Yallop criterion).
Parameters:
- date number Fixed date.
- location table Location table.
Returns:
-
boolean