mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-12-23 10:34:07 +00:00
396 lines
16 KiB
EmacsLisp
396 lines
16 KiB
EmacsLisp
;;; lunar.el --- calendar functions for phases of the moon.
|
|
|
|
;; Copyright (C) 1992, 1993, 1995, 1997 Free Software Foundation, Inc.
|
|
|
|
;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
|
|
;; Keywords: calendar
|
|
;; Human-Keywords: moon, lunar phases, calendar, diary
|
|
|
|
;; This file is part of GNU Emacs.
|
|
|
|
;; GNU Emacs is free software; you can redistribute it and/or modify
|
|
;; it under the terms of the GNU General Public License as published by
|
|
;; the Free Software Foundation; either version 2, or (at your option)
|
|
;; any later version.
|
|
|
|
;; GNU Emacs is distributed in the hope that it will be useful,
|
|
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
;; GNU General Public License for more details.
|
|
|
|
;; You should have received a copy of the GNU General Public License
|
|
;; along with GNU Emacs; see the file COPYING. If not, write to the
|
|
;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
;; Boston, MA 02111-1307, USA.
|
|
|
|
;;; Commentary:
|
|
|
|
;; This collection of functions implements lunar phases for calendar.el and
|
|
;; diary.el.
|
|
|
|
;; Based on ``Astronomical Formulae for Calculators,'' 3rd ed., by Jean Meeus,
|
|
;; Willmann-Bell, Inc., 1985 and ``Astronomical Algorithms'' by Jean Meeus,
|
|
;; Willmann-Bell, Inc., 1991.
|
|
;;
|
|
;; WARNING: The calculations will be accurate only to within a few minutes.
|
|
|
|
;; The author would be delighted to have an astronomically more sophisticated
|
|
;; person rewrite the code for the lunar calculations in this file!
|
|
|
|
;; Technical details of all the calendrical calculations can be found in
|
|
;; ``Calendrical Calculations'' by Nachum Dershowitz and Edward M. Reingold,
|
|
;; Cambridge University Press (1997).
|
|
|
|
;; Comments, corrections, and improvements should be sent to
|
|
;; Edward M. Reingold Department of Computer Science
|
|
;; (217) 333-6733 University of Illinois at Urbana-Champaign
|
|
;; reingold@cs.uiuc.edu 1304 West Springfield Avenue
|
|
;; Urbana, Illinois 61801
|
|
|
|
;;; Code:
|
|
|
|
(if (fboundp 'atan)
|
|
(require 'lisp-float-type)
|
|
(error "Lunar calculations impossible since floating point is unavailable."))
|
|
|
|
(require 'solar)
|
|
|
|
(defun lunar-phase-list (month year)
|
|
"List of lunar phases for three months starting with Gregorian MONTH, YEAR."
|
|
(let ((end-month month)
|
|
(end-year year)
|
|
(start-month month)
|
|
(start-year year))
|
|
(increment-calendar-month end-month end-year 3)
|
|
(increment-calendar-month start-month start-year -1)
|
|
(let* ((end-date (list (list end-month 1 end-year)))
|
|
(start-date (list (list start-month
|
|
(calendar-last-day-of-month
|
|
start-month start-year)
|
|
start-year)))
|
|
(index (* 4
|
|
(truncate
|
|
(* 12.3685
|
|
(+ year
|
|
( / (calendar-day-number (list month 1 year))
|
|
366.0)
|
|
-1900)))))
|
|
(new-moon (lunar-phase index))
|
|
(list))
|
|
(while (calendar-date-compare new-moon end-date)
|
|
(if (calendar-date-compare start-date new-moon)
|
|
(setq list (append list (list new-moon))))
|
|
(setq index (1+ index))
|
|
(setq new-moon (lunar-phase index)))
|
|
list)))
|
|
|
|
(defun lunar-phase (index)
|
|
"Local date and time of lunar phase INDEX.
|
|
Integer below INDEX/4 gives the lunation number, counting from Jan 1, 1900;
|
|
remainder mod 4 gives the phase: 0 new moon, 1 first quarter, 2 full moon,
|
|
3 last quarter."
|
|
(let* ((phase (mod index 4))
|
|
(index (/ index 4.0))
|
|
(time (/ index 1236.85))
|
|
(date (+ (calendar-absolute-from-gregorian '(1 0.5 1900))
|
|
0.75933
|
|
(* 29.53058868 index)
|
|
(* 0.0001178 time time)
|
|
(* -0.000000155 time time time)
|
|
(* 0.00033
|
|
(solar-sin-degrees (+ 166.56
|
|
(* 132.87 time)
|
|
(* -0.009173 time time))))))
|
|
(sun-anomaly (mod
|
|
(+ 359.2242
|
|
(* 29.105356 index)
|
|
(* -0.0000333 time time)
|
|
(* -0.00000347 time time time))
|
|
360.0))
|
|
(moon-anomaly (mod
|
|
(+ 306.0253
|
|
(* 385.81691806 index)
|
|
(* 0.0107306 time time)
|
|
(* 0.00001236 time time time))
|
|
360.0))
|
|
(moon-lat (mod
|
|
(+ 21.2964
|
|
(* 390.67050646 index)
|
|
(* -0.0016528 time time)
|
|
(* -0.00000239 time time time))
|
|
360.0))
|
|
(adjustment
|
|
(if (memq phase '(0 2))
|
|
(+ (* (- 0.1734 (* 0.000393 time))
|
|
(solar-sin-degrees sun-anomaly))
|
|
(* 0.0021 (solar-sin-degrees (* 2 sun-anomaly)))
|
|
(* -0.4068 (solar-sin-degrees moon-anomaly))
|
|
(* 0.0161 (solar-sin-degrees (* 2 moon-anomaly)))
|
|
(* -0.0004 (solar-sin-degrees (* 3 moon-anomaly)))
|
|
(* 0.0104 (solar-sin-degrees (* 2 moon-lat)))
|
|
(* -0.0051 (solar-sin-degrees (+ sun-anomaly moon-anomaly)))
|
|
(* -0.0074 (solar-sin-degrees (- sun-anomaly moon-anomaly)))
|
|
(* 0.0004 (solar-sin-degrees (+ (* 2 moon-lat) sun-anomaly)))
|
|
(* -0.0004 (solar-sin-degrees (- (* 2 moon-lat) sun-anomaly)))
|
|
(* -0.0006 (solar-sin-degrees
|
|
(+ (* 2 moon-lat) moon-anomaly)))
|
|
(* 0.0010 (solar-sin-degrees (- (* 2 moon-lat) moon-anomaly)))
|
|
(* 0.0005 (solar-sin-degrees
|
|
(+ (* 2 moon-anomaly) sun-anomaly))))
|
|
(+ (* (- 0.1721 (* 0.0004 time))
|
|
(solar-sin-degrees sun-anomaly))
|
|
(* 0.0021 (solar-sin-degrees (* 2 sun-anomaly)))
|
|
(* -0.6280 (solar-sin-degrees moon-anomaly))
|
|
(* 0.0089 (solar-sin-degrees (* 2 moon-anomaly)))
|
|
(* -0.0004 (solar-sin-degrees (* 3 moon-anomaly)))
|
|
(* 0.0079 (solar-sin-degrees (* 2 moon-lat)))
|
|
(* -0.0119 (solar-sin-degrees (+ sun-anomaly moon-anomaly)))
|
|
(* -0.0047 (solar-sin-degrees (- sun-anomaly moon-anomaly)))
|
|
(* 0.0003 (solar-sin-degrees (+ (* 2 moon-lat) sun-anomaly)))
|
|
(* -0.0004 (solar-sin-degrees (- (* 2 moon-lat) sun-anomaly)))
|
|
(* -0.0006 (solar-sin-degrees (+ (* 2 moon-lat) moon-anomaly)))
|
|
(* 0.0021 (solar-sin-degrees (- (* 2 moon-lat) moon-anomaly)))
|
|
(* 0.0003 (solar-sin-degrees
|
|
(+ (* 2 moon-anomaly) sun-anomaly)))
|
|
(* 0.0004 (solar-sin-degrees
|
|
(- sun-anomaly (* 2 moon-anomaly))))
|
|
(* -0.0003 (solar-sin-degrees
|
|
(+ (* 2 sun-anomaly) moon-anomaly))))))
|
|
(adj (+ 0.0028
|
|
(* -0.0004 (solar-cosine-degrees
|
|
sun-anomaly))
|
|
(* 0.0003 (solar-cosine-degrees
|
|
moon-anomaly))))
|
|
(adjustment (cond ((= phase 1) (+ adjustment adj))
|
|
((= phase 2) (- adjustment adj))
|
|
(t adjustment)))
|
|
(date (+ date adjustment))
|
|
(date (+ date (/ (- calendar-time-zone
|
|
(solar-ephemeris-correction
|
|
(extract-calendar-year
|
|
(calendar-gregorian-from-absolute
|
|
(truncate date)))))
|
|
60.0 24.0)))
|
|
(time (* 24 (- date (truncate date))))
|
|
(date (calendar-gregorian-from-absolute (truncate date)))
|
|
(adj (dst-adjust-time date time)))
|
|
(list (car adj) (apply 'solar-time-string (cdr adj)) phase)))
|
|
|
|
(defun lunar-phase-name (phase)
|
|
"Name of lunar PHASE.
|
|
0 = new moon, 1 = first quarter, 2 = full moon, 3 = last quarter."
|
|
(cond ((= 0 phase) "New Moon")
|
|
((= 1 phase) "First Quarter Moon")
|
|
((= 2 phase) "Full Moon")
|
|
((= 3 phase) "Last Quarter Moon")))
|
|
|
|
(defun calendar-phases-of-moon ()
|
|
"Create a buffer with the lunar phases for the current calendar window."
|
|
(interactive)
|
|
(message "Computing phases of the moon...")
|
|
(let ((m1 displayed-month)
|
|
(y1 displayed-year)
|
|
(m2 displayed-month)
|
|
(y2 displayed-year))
|
|
(increment-calendar-month m1 y1 -1)
|
|
(increment-calendar-month m2 y2 1)
|
|
(set-buffer (get-buffer-create lunar-phases-buffer))
|
|
(setq buffer-read-only nil)
|
|
(calendar-set-mode-line
|
|
(if (= y1 y2)
|
|
(format "Phases of the Moon from %s to %s, %d%%-"
|
|
(calendar-month-name m1) (calendar-month-name m2) y2)
|
|
(format "Phases of the Moon from %s, %d to %s, %d%%-"
|
|
(calendar-month-name m1) y1 (calendar-month-name m2) y2)))
|
|
(erase-buffer)
|
|
(insert
|
|
(mapconcat
|
|
'(lambda (x)
|
|
(let ((date (car x))
|
|
(time (car (cdr x)))
|
|
(phase (car (cdr (cdr x)))))
|
|
(concat (calendar-date-string date)
|
|
": "
|
|
(lunar-phase-name phase)
|
|
" "
|
|
time)))
|
|
(lunar-phase-list m1 y1) "\n"))
|
|
(goto-char (point-min))
|
|
(set-buffer-modified-p nil)
|
|
(setq buffer-read-only t)
|
|
(display-buffer lunar-phases-buffer)
|
|
(message "Computing phases of the moon...done")))
|
|
|
|
;;;###autoload
|
|
(defun phases-of-moon (&optional arg)
|
|
"Display the quarters of the moon for last month, this month, and next month.
|
|
If called with an optional prefix argument, prompts for month and year.
|
|
|
|
This function is suitable for execution in a .emacs file."
|
|
(interactive "P")
|
|
(save-excursion
|
|
(let* ((date (if arg
|
|
(calendar-read-date t)
|
|
(calendar-current-date)))
|
|
(displayed-month (extract-calendar-month date))
|
|
(displayed-year (extract-calendar-year date)))
|
|
(calendar-phases-of-moon))))
|
|
|
|
(defun diary-phases-of-moon ()
|
|
"Moon phases diary entry."
|
|
(let* ((index (* 4
|
|
(truncate
|
|
(* 12.3685
|
|
(+ (extract-calendar-year date)
|
|
( / (calendar-day-number date)
|
|
366.0)
|
|
-1900)))))
|
|
(phase (lunar-phase index)))
|
|
(while (calendar-date-compare phase (list date))
|
|
(setq index (1+ index))
|
|
(setq phase (lunar-phase index)))
|
|
(if (calendar-date-equal (car phase) date)
|
|
(concat (lunar-phase-name (car (cdr (cdr phase)))) " "
|
|
(car (cdr phase))))))
|
|
|
|
|
|
;; For the Chinese calendar the calculations for the new moon need to be more
|
|
;; accurate than those above, so we use more terms in the approximation.
|
|
|
|
(defun lunar-new-moon-time (k)
|
|
"Astronomical (Julian) day number of K th new moon."
|
|
(let* ((T (/ k 1236.85))
|
|
(T2 (* T T))
|
|
(T3 (* T T T))
|
|
(T4 (* T2 T2))
|
|
(JDE (+ 2451550.09765
|
|
(* 29.530588853 k)
|
|
(* 0.0001337 T2)
|
|
(* -0.000000150 T3)
|
|
(* 0.00000000073 T4)))
|
|
(E (- 1 (* 0.002516 T) (* 0.0000074 T2)))
|
|
(sun-anomaly (+ 2.5534
|
|
(* 29.10535669 k)
|
|
(* -0.0000218 T2)
|
|
(* -0.00000011 T3)))
|
|
(moon-anomaly (+ 201.5643
|
|
(* 385.81693528 k)
|
|
(* 0.0107438 T2)
|
|
(* 0.00001239 T3)
|
|
(* -0.000000058 T4)))
|
|
(moon-argument (+ 160.7108
|
|
(* 390.67050274 k)
|
|
(* -0.0016341 T2)
|
|
(* -0.00000227 T3)
|
|
(* 0.000000011 T4)))
|
|
(omega (+ 124.7746
|
|
(* -1.56375580 k)
|
|
(* 0.0020691 T2)
|
|
(* 0.00000215 T3)))
|
|
(A1 (+ 299.77 (* 0.107408 k) (* -0.009173 T2)))
|
|
(A2 (+ 251.88 (* 0.016321 k)))
|
|
(A3 (+ 251.83 (* 26.641886 k)))
|
|
(A4 (+ 349.42 (* 36.412478 k)))
|
|
(A5 (+ 84.66 (* 18.206239 k)))
|
|
(A6 (+ 141.74 (* 53.303771 k)))
|
|
(A7 (+ 207.14 (* 2.453732 k)))
|
|
(A8 (+ 154.84 (* 7.306860 k)))
|
|
(A9 (+ 34.52 (* 27.261239 k)))
|
|
(A10 (+ 207.19 (* 0.121824 k)))
|
|
(A11 (+ 291.34 (* 1.844379 k)))
|
|
(A12 (+ 161.72 (* 24.198154 k)))
|
|
(A13 (+ 239.56 (* 25.513099 k)))
|
|
(A14 (+ 331.55 (* 3.592518 k)))
|
|
(correction
|
|
(+ (* -0.40720 (solar-sin-degrees moon-anomaly))
|
|
(* 0.17241 E (solar-sin-degrees sun-anomaly))
|
|
(* 0.01608 (solar-sin-degrees (* 2 moon-anomaly)))
|
|
(* 0.01039 (solar-sin-degrees (* 2 moon-argument)))
|
|
(* 0.00739 E (solar-sin-degrees (- moon-anomaly sun-anomaly)))
|
|
(* -0.00514 E (solar-sin-degrees (+ moon-anomaly sun-anomaly)))
|
|
(* 0.00208 E E (solar-sin-degrees (* 2 sun-anomaly)))
|
|
(* -0.00111 (solar-sin-degrees
|
|
(- moon-anomaly (* 2 moon-argument))))
|
|
(* -0.00057 (solar-sin-degrees
|
|
(+ moon-anomaly (* 2 moon-argument))))
|
|
(* 0.00056 E (solar-sin-degrees
|
|
(+ (* 2 moon-anomaly) sun-anomaly)))
|
|
(* -0.00042 (solar-sin-degrees (* 3 moon-anomaly)))
|
|
(* 0.00042 E (solar-sin-degrees
|
|
(+ sun-anomaly (* 2 moon-argument))))
|
|
(* 0.00038 E (solar-sin-degrees
|
|
(- sun-anomaly (* 2 moon-argument))))
|
|
(* -0.00024 E (solar-sin-degrees
|
|
(- (* 2 moon-anomaly) sun-anomaly)))
|
|
(* -0.00017 (solar-sin-degrees omega))
|
|
(* -0.00007 (solar-sin-degrees
|
|
(+ moon-anomaly (* 2 sun-anomaly))))
|
|
(* 0.00004 (solar-sin-degrees
|
|
(- (* 2 moon-anomaly) (* 2 moon-argument))))
|
|
(* 0.00004 (solar-sin-degrees (* 3 sun-anomaly)))
|
|
(* 0.00003 (solar-sin-degrees (+ moon-anomaly sun-anomaly
|
|
(* -2 moon-argument))))
|
|
(* 0.00003 (solar-sin-degrees
|
|
(+ (* 2 moon-anomaly) (* 2 moon-argument))))
|
|
(* -0.00003 (solar-sin-degrees (+ moon-anomaly sun-anomaly
|
|
(* 2 moon-argument))))
|
|
(* 0.00003 (solar-sin-degrees (- moon-anomaly sun-anomaly
|
|
(* -2 moon-argument))))
|
|
(* -0.00002 (solar-sin-degrees (- moon-anomaly sun-anomaly
|
|
(* 2 moon-argument))))
|
|
(* -0.00002 (solar-sin-degrees
|
|
(+ (* 3 moon-anomaly) sun-anomaly)))
|
|
(* 0.00002 (solar-sin-degrees (* 4 moon-anomaly)))))
|
|
(additional
|
|
(+ (* 0.000325 (solar-sin-degrees A1))
|
|
(* 0.000165 (solar-sin-degrees A2))
|
|
(* 0.000164 (solar-sin-degrees A3))
|
|
(* 0.000126 (solar-sin-degrees A4))
|
|
(* 0.000110 (solar-sin-degrees A5))
|
|
(* 0.000062 (solar-sin-degrees A6))
|
|
(* 0.000060 (solar-sin-degrees A7))
|
|
(* 0.000056 (solar-sin-degrees A8))
|
|
(* 0.000047 (solar-sin-degrees A9))
|
|
(* 0.000042 (solar-sin-degrees A10))
|
|
(* 0.000040 (solar-sin-degrees A11))
|
|
(* 0.000037 (solar-sin-degrees A12))
|
|
(* 0.000035 (solar-sin-degrees A13))
|
|
(* 0.000023 (solar-sin-degrees A14))))
|
|
(newJDE (+ JDE correction additional)))
|
|
(+ newJDE
|
|
(- (solar-ephemeris-correction
|
|
(extract-calendar-year
|
|
(calendar-gregorian-from-absolute
|
|
(floor (calendar-absolute-from-astro newJDE))))))
|
|
(/ calendar-time-zone 60.0 24.0))))
|
|
|
|
(defun lunar-new-moon-on-or-after (d)
|
|
"Astronomical (Julian) day number of first new moon on or after astronomical
|
|
\(Julian) day number d. The fractional part is the time of day.
|
|
|
|
The date and time are local time, including any daylight savings rules,
|
|
as governed by the values of calendar-daylight-savings-starts,
|
|
calendar-daylight-savings-starts-time, calendar-daylight-savings-ends,
|
|
calendar-daylight-savings-ends-time, calendar-daylight-time-offset, and
|
|
calendar-time-zone."
|
|
(let* ((date (calendar-gregorian-from-absolute
|
|
(floor (calendar-absolute-from-astro d))))
|
|
(year (+ (extract-calendar-year date)
|
|
(/ (calendar-day-number date) 365.25)))
|
|
(k (floor (* (- year 2000.0) 12.3685)))
|
|
(date (lunar-new-moon-time k)))
|
|
(while (< date d)
|
|
(setq k (1+ k))
|
|
(setq date (lunar-new-moon-time k)))
|
|
(let* ((a-date (calendar-absolute-from-astro date))
|
|
(time (* 24 (- a-date (truncate a-date))))
|
|
(date (calendar-gregorian-from-absolute (truncate a-date)))
|
|
(adj (dst-adjust-time date time)))
|
|
(calendar-astro-from-absolute
|
|
(+ (calendar-absolute-from-gregorian (car adj))
|
|
(/ (car (cdr adj)) 24.0))))))
|
|
|
|
(provide 'lunar)
|
|
|
|
;;; lunar.el ends here
|