(diary-show-all-entries): Do not refer to

[gnu-emacs] / lisp / calendar / solar.el

diff --git a/lisp/calendar/solar.el b/lisp/calendar/solar.el
index 30bd74ca46271409f35c7b6d3379929b5f2be6dd..660abb14f885e5c0f4a0faa35ae92781ed98cf85 100644 (file)
--- a/lisp/calendar/solar.el
+++ b/lisp/calendar/solar.el
@@ -1,9 +1,11 @@
-;;; solar.el --- calendar functions for solar events.
+;;; solar.el --- calendar functions for solar events

 
 

-;; Copyright (C) 1992, 1993, 1995, 1997 Free Software Foundation, Inc.
+;; Copyright (C) 1992, 1993, 1995, 1997, 2001, 2002, 2003, 2004, 2005,
+;;   2006  Free Software Foundation, Inc.

 
 ;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
 ;;     Denis B. Roegel <Denis.Roegel@loria.fr>
 
 ;; Author: Edward M. Reingold <reingold@cs.uiuc.edu>
 ;;     Denis B. Roegel <Denis.Roegel@loria.fr>

+;; Maintainer: Glenn Morris <rgm@gnu.org>

 ;; Keywords: calendar
 ;; Human-Keywords: sunrise, sunset, equinox, solstice, calendar, diary,
 ;;     holidays
 ;; Keywords: calendar
 ;; Human-Keywords: sunrise, sunset, equinox, solstice, calendar, diary,
 ;;     holidays


@@ -22,8 +24,8 @@
 
 ;; 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
 
 ;; 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.
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.

 
 ;;; Commentary:
 
 
 ;;; Commentary:
 


@@ -47,6 +49,10 @@
 ;;    2. Equinox/solstice times will be accurate to the minute for years
 ;;       1951--2050.  For other years the times will be within +/- 1 minute.
 
 ;;    2. Equinox/solstice times will be accurate to the minute for years
 ;;       1951--2050.  For other years the times will be within +/- 1 minute.
 

+;; Technical details of all the calendrical calculations can be found in
+;; ``Calendrical Calculations: The Millennium Edition'' by Edward M. Reingold
+;; and Nachum Dershowitz, Cambridge University Press (2001).
+

 ;; Comments, corrections, and improvements should be sent to
 ;;  Edward M. Reingold               Department of Computer Science
 ;;  (217) 333-6733                   University of Illinois at Urbana-Champaign
 ;; Comments, corrections, and improvements should be sent to
 ;;  Edward M. Reingold               Department of Computer Science
 ;;  (217) 333-6733                   University of Illinois at Urbana-Champaign


@@ -55,9 +61,13 @@
 
 ;;; Code:
 
 
 ;;; Code:
 

+(defvar date)
+(defvar displayed-month)
+(defvar displayed-year)
+

 (if (fboundp 'atan)
     (require 'lisp-float-type)
 (if (fboundp 'atan)
     (require 'lisp-float-type)

-  (error "Solar/lunar calculations impossible since floating point is unavailable."))
+  (error "Solar/lunar calculations impossible since floating point is unavailable"))

 
 (require 'cal-dst)
 (require 'cal-julian)
 
 (require 'cal-dst)
 (require 'cal-julian)


@@ -69,8 +79,8 @@
   "*The pseudo-pattern that governs the way a time of day is formatted.
 
 A pseudo-pattern is a list of expressions that can involve the keywords
   "*The pseudo-pattern that governs the way a time of day is formatted.
 
 A pseudo-pattern is a list of expressions that can involve the keywords

-`12-hours', `24-hours', and `minutes',  all numbers in string form,
-and `am-pm' and `time-zone',  both alphabetic strings.
+`12-hours', `24-hours', and `minutes', all numbers in string form,
+and `am-pm' and `time-zone', both alphabetic strings.

 
 For example, the form
 
 
 For example, the form
 


@@ -159,7 +169,7 @@ This variable should be set in `site-start'.el."
              (if (numberp calendar-longitude)
                  (if (> calendar-longitude 0) "E" "W")
                (if (equal (aref calendar-longitude 2) 'east) "E" "W"))))
              (if (numberp calendar-longitude)
                  (if (> calendar-longitude 0) "E" "W")
                (if (equal (aref calendar-longitude 2) 'east) "E" "W"))))

-  "*Expression evaluating to name of `calendar-longitude', calendar-latitude'.
+  "*Expression evaluating to name of `calendar-longitude', `calendar-latitude'.

 For example, \"New York City\".  Default value is just the latitude, longitude
 pair.
 
 For example, \"New York City\".  Default value is just the latitude, longitude
 pair.
 


@@ -190,12 +200,12 @@ delta.  At present, delta = 0.01 degrees, so the value of the variable
   '("Autumnal Equinox" "Winter Solstice" "Vernal Equinox" "Summer Solstice")
   "List of season changes for the southern hemisphere.")
 
   '("Autumnal Equinox" "Winter Solstice" "Vernal Equinox" "Summer Solstice")
   "List of season changes for the southern hemisphere.")
 

-(defvar solar-sidereal-time-greenwich-midnight 
-   nil 
+(defvar solar-sidereal-time-greenwich-midnight
+   nil

    "Sidereal time at Greenwich at midnight (universal time).")
 
    "Sidereal time at Greenwich at midnight (universal time).")
 

-(defvar solar-spring-or-summer-season nil  
-  "T if spring or summer and nil otherwise.
+(defvar solar-northern-spring-or-summer-season nil
+  "Non-nil if northern spring or summer and nil otherwise.

 Needed for polar areas, in order to know whether the day lasts 0 or 24 hours.")
 
 (defun solar-setup ()
 Needed for polar areas, in order to know whether the day lasts 0 or 24 hours.")
 
 (defun solar-setup ()


@@ -219,7 +229,7 @@ Needed for polar areas, in order to know whether the day lasts 0 or 24 hours.")
 Returns nil if nothing was entered."
   (let ((x (read-string prompt "")))
     (if (not (string-equal x ""))
 Returns nil if nothing was entered."
   (let ((x (read-string prompt "")))
     (if (not (string-equal x ""))

-        (string-to-int x))))
+        (string-to-number x))))

 
 ;; The condition-case stuff is needed to catch bogus arithmetic
 ;; exceptions that occur on some machines (like Sparcs)
 
 ;; The condition-case stuff is needed to catch bogus arithmetic
 ;; exceptions that occur on some machines (like Sparcs)


@@ -235,7 +245,7 @@ Returns nil if nothing was entered."
   (condition-case nil
       (tan (degrees-to-radians (mod x 360.0)))
     (solar-tangent-degrees x)))
   (condition-case nil
       (tan (degrees-to-radians (mod x 360.0)))
     (solar-tangent-degrees x)))

-      
+

 (defun solar-xy-to-quadrant (x y)
   "Determines the quadrant of the point X, Y."
   (if (> x 0)
 (defun solar-xy-to-quadrant (x y)
   "Determines the quadrant of the point X, Y."
   (if (> x 0)


@@ -258,7 +268,7 @@ Returns nil if nothing was entered."
    "Arctan of point X, Y."
    (if (= x 0)
        (if (> y 0) 90 270)
    "Arctan of point X, Y."
    (if (= x 0)
        (if (> y 0) 90 270)

-     (solar-arctan (/ y x) x)))
+     (solar-arctan (/ y x) (solar-xy-to-quadrant x y))))

 
 (defun solar-arccos (x)
      "Arcos of X."
 
 (defun solar-arccos (x)
      "Arcos of X."


@@ -294,8 +304,8 @@ Both arguments are in degrees."
    (* (solar-sin-degrees obliquity)
       (solar-sin-degrees longitude))))
 
    (* (solar-sin-degrees obliquity)
       (solar-sin-degrees longitude))))
 

-(defun solar-sunrise-and-sunset (time latitude longitude)
-  "Sunrise, sunset and length of day. 
+(defun solar-sunrise-and-sunset (time latitude longitude height)
+  "Sunrise, sunset and length of day.

 Parameters are the midday TIME and the LATITUDE, LONGITUDE of the location.
 
 TIME is a pair with the first component being the number of Julian centuries
 Parameters are the midday TIME and the LATITUDE, LONGITUDE of the location.
 
 TIME is a pair with the first component being the number of Julian centuries


@@ -304,22 +314,28 @@ time.  For instance, the pair corresponding to November 28, 1995 at 16 UT is
 \(-0.040945 16), -0.040945 being the number of julian centuries elapsed between
 Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT.
 
 \(-0.040945 16), -0.040945 being the number of julian centuries elapsed between
 Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT.
 

-Coordinates are included because this function is called with latitude=10
+HEIGHT is the angle the center of the sun has over the horizon for the contact
+we are trying to find. For sunrise and sunset, it is usually -0.61 degrees,
+accounting for the edge of the sun being on the horizon.
+
+Coordinates are included because this function is called with latitude=1

 degrees to find out if polar regions have 24 hours of sun or only night."
 degrees to find out if polar regions have 24 hours of sun or only night."

-  (let* ((rise-time (solar-moment -1 latitude longitude time))
-         (set-time (solar-moment 1 latitude longitude time))
+  (let* ((rise-time (solar-moment -1 latitude longitude time height))
+         (set-time (solar-moment 1 latitude longitude time height))

          (day-length))
     (if (not (and rise-time set-time))
          (day-length))
     (if (not (and rise-time set-time))

-        (if (or (and (> latitude 0) solar-spring-or-summer-season)
-                (and (< latitude 0) (not solar-spring-or-summer-season)))
-          (setq day-length 24)
-          (setq day-length 0))
-        (setq day-length (- set-time rise-time)))
+        (if (or (and (> latitude 0)
+                     solar-northern-spring-or-summer-season)
+                (and (< latitude 0)
+                     (not solar-northern-spring-or-summer-season)))
+            (setq day-length 24)
+         (setq day-length 0))
+      (setq day-length (- set-time rise-time)))

     (list (if rise-time (+ rise-time (/ calendar-time-zone 60.0)) nil)
           (if set-time (+ set-time (/ calendar-time-zone 60.0)) nil)
           day-length)))
 
     (list (if rise-time (+ rise-time (/ calendar-time-zone 60.0)) nil)
           (if set-time (+ set-time (/ calendar-time-zone 60.0)) nil)
           day-length)))
 

-(defun solar-moment (direction latitude longitude time)
+(defun solar-moment (direction latitude longitude time height)

   "Sunrise/sunset at location.
 Sunrise if DIRECTION =-1 or sunset if =1 at LATITUDE, LONGITUDE, with midday
 being TIME.
   "Sunrise/sunset at location.
 Sunrise if DIRECTION =-1 or sunset if =1 at LATITUDE, LONGITUDE, with midday
 being TIME.


@@ -330,41 +346,45 @@ time.  For instance, the pair corresponding to November 28, 1995 at 16 UT is
 \(-0.040945 16), -0.040945 being the number of julian centuries elapsed between
 Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT.
 
 \(-0.040945 16), -0.040945 being the number of julian centuries elapsed between
 Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT.
 

+HEIGHT is the angle the center of the sun has over the horizon for the contact
+we are trying to find. For sunrise and sunset, it is usually -0.61 degrees,
+accounting for the edge of the sun being on the horizon.
+

 Uses binary search."
   (let* ((ut (car (cdr time)))
 Uses binary search."
   (let* ((ut (car (cdr time)))

-         (possible 1) ; we assume that rise or set are possible
-         (utmin (+ ut (* direction 12.0))) 
+         (possible t) ; we assume that rise or set are possible
+         (utmin (+ ut (* direction 12.0)))

          (utmax ut)    ; the time searched is between utmin and utmax
             ; utmin and utmax are in hours
          (utmoment-old 0.0)    ; rise or set approximation
          (utmoment 1.0) ; rise or set approximation
          (hut 0)         ; sun height at utmoment
          (t0 (car time))
          (utmax ut)    ; the time searched is between utmin and utmax
             ; utmin and utmax are in hours
          (utmoment-old 0.0)    ; rise or set approximation
          (utmoment 1.0) ; rise or set approximation
          (hut 0)         ; sun height at utmoment
          (t0 (car time))

-         (hmin (car (cdr 
-               (solar-horizontal-coordinates (list t0 utmin) 
+         (hmin (car (cdr
+               (solar-horizontal-coordinates (list t0 utmin)

                                                 latitude longitude t))))
                                                 latitude longitude t))))

-         (hmax (car (cdr 
-               (solar-horizontal-coordinates (list t0 utmax) 
+         (hmax (car (cdr
+               (solar-horizontal-coordinates (list t0 utmax)

                                                 latitude longitude t)))))
        ; -0.61 degrees is the height of the middle of the sun, when it rises
        ;   or sets.
                                                 latitude longitude t)))))
        ; -0.61 degrees is the height of the middle of the sun, when it rises
        ;   or sets.

-     (if (< hmin -0.61) 
-              (if (> hmax -0.61)
+     (if (< hmin height)
+              (if (> hmax height)

                   (while ;(< i 20) ; we perform a simple dichotomy
                   (while ;(< i 20) ; we perform a simple dichotomy

-                         ; (> (abs (+ hut 0.61)) epsilon)
+                         ; (> (abs (- hut height)) epsilon)

                          (>= (abs (- utmoment utmoment-old))
                              (/ solar-error 60))
                     (setq utmoment-old utmoment)
                     (setq utmoment (/ (+ utmin utmax) 2))
                          (>= (abs (- utmoment utmoment-old))
                              (/ solar-error 60))
                     (setq utmoment-old utmoment)
                     (setq utmoment (/ (+ utmin utmax) 2))

-                    (setq hut (car (cdr 
-                                    (solar-horizontal-coordinates 
+                    (setq hut (car (cdr
+                                    (solar-horizontal-coordinates

                                    (list t0 utmoment) latitude longitude t))))
                                    (list t0 utmoment) latitude longitude t))))

-                    (if (< hut -0.61) (setq utmin utmoment))
-                    (if (> hut -0.61) (setq utmax utmoment))
+                    (if (< hut height) (setq utmin utmoment))
+                    (if (> hut height) (setq utmax utmoment))

                    )
                    )

-                (setq possible 0)) ; the sun never rises
-                (setq possible 0)) ; the sun never sets
-     (if (equal possible 0) nil utmoment)))
+                (setq possible nil)) ; the sun never rises
+                (setq possible nil)) ; the sun never sets
+     (if (not possible) nil utmoment)))

 
 (defun solar-time-string (time time-zone)
   "Printable form for decimal fraction TIME in TIME-ZONE.
 
 (defun solar-time-string (time time-zone)
   "Printable form for decimal fraction TIME in TIME-ZONE.


@@ -385,7 +405,7 @@ Format used is given by `calendar-time-display-form'."
           (floor (* 60 (- time (floor time))))))
 
 (defun solar-exact-local-noon (date)
           (floor (* 60 (- time (floor time))))))
 
 (defun solar-exact-local-noon (date)

-  "Date and Universal Time of local noon at *local date* date. 
+  "Date and Universal Time of local noon at *local date* date.

 
 The date may be different from the one asked for, but it will be the right
 local date.  The second component of date should be an integer."
 
 The date may be different from the one asked for, but it will be the right
 local date.  The second component of date should be an integer."


@@ -394,12 +414,12 @@ local date.  The second component of date should be an integer."
          (te (solar-time-equation date ut)))
     (setq ut (- ut te))
     (if (>= ut 24)
          (te (solar-time-equation date ut)))
     (setq ut (- ut te))
     (if (>= ut 24)

-        (progn 
+        (progn

           (setq nd (list (car date) (+ 1 (car (cdr date)))
                          (car (cdr (cdr date)))))
           (setq ut (- ut 24))))
     (if (< ut 0)
           (setq nd (list (car date) (+ 1 (car (cdr date)))
                          (car (cdr (cdr date)))))
           (setq ut (- ut 24))))
     (if (< ut 0)

-        (progn 
+        (progn

           (setq nd (list (car date) (- (car (cdr date)) 1)
                          (car (cdr (cdr date)))))
           (setq ut (+ ut 24))))
           (setq nd (list (car date) (- (car (cdr date)) 1)
                          (car (cdr (cdr date)))))
           (setq ut (+ ut 24))))


@@ -414,29 +434,29 @@ local date.  The second component of date should be an integer."
 Corresponding value is nil if there is no sunrise/sunset."
   (let* (; first, get the exact moment of local noon.
          (exact-local-noon (solar-exact-local-noon date))
 Corresponding value is nil if there is no sunrise/sunset."
   (let* (; first, get the exact moment of local noon.
          (exact-local-noon (solar-exact-local-noon date))

-         ; get the the time from the 2000 epoch.
+         ; get the time from the 2000 epoch.

          (t0 (solar-julian-ut-centuries (car exact-local-noon)))
          ; store the sidereal time at Greenwich at midnight of UT time.
          ; find if summer or winter slightly above the equator
          (equator-rise-set
          (t0 (solar-julian-ut-centuries (car exact-local-noon)))
          ; store the sidereal time at Greenwich at midnight of UT time.
          ; find if summer or winter slightly above the equator
          (equator-rise-set

-          (progn (setq solar-sidereal-time-greenwich-midnight 
+          (progn (setq solar-sidereal-time-greenwich-midnight

                        (solar-sidereal-time t0))
                        (solar-sidereal-time t0))

-                 (solar-sunrise-and-sunset 
+                 (solar-sunrise-and-sunset

                   (list t0 (car (cdr exact-local-noon)))
                   (list t0 (car (cdr exact-local-noon)))

-                  10.0
-                  (calendar-longitude))))
+                  1.0
+                  (calendar-longitude) 0)))

          ; store the spring/summer information,
          ; compute sunrise and sunset (two first components of rise-set).
          ; length of day is the third component (it is only the difference
          ; between sunset and sunrise when there is a sunset and a sunrise)
          (rise-set
           (progn
          ; store the spring/summer information,
          ; compute sunrise and sunset (two first components of rise-set).
          ; length of day is the third component (it is only the difference
          ; between sunset and sunrise when there is a sunset and a sunrise)
          (rise-set
           (progn

-            (setq solar-spring-or-summer-season 
-                  (if (> (car (cdr (cdr equator-rise-set))) 12) 1 0))
-            (solar-sunrise-and-sunset 
+            (setq solar-northern-spring-or-summer-season
+                  (if (> (car (cdr (cdr equator-rise-set))) 12) t nil))
+            (solar-sunrise-and-sunset

              (list t0 (car (cdr exact-local-noon)))
              (calendar-latitude)
              (list t0 (car (cdr exact-local-noon)))
              (calendar-latitude)

-             (calendar-longitude))))
+             (calendar-longitude) -0.61)))

          (rise (car rise-set))
          (adj-rise (if rise (dst-adjust-time date rise) nil))
          (set (car (cdr rise-set)))
          (rise (car rise-set))
          (adj-rise (if rise (dst-adjust-time date rise) nil))
          (set (car (cdr rise-set)))


@@ -463,10 +483,10 @@ Corresponding value is nil if there is no sunrise/sunset."
 
 (defun solar-julian-ut-centuries (date)
   "Number of Julian centuries elapsed since 1 Jan, 2000 at noon  U.T. for Gregorian DATE."
 
 (defun solar-julian-ut-centuries (date)
   "Number of Julian centuries elapsed since 1 Jan, 2000 at noon  U.T. for Gregorian DATE."

-  (/ (- (calendar-absolute-from-gregorian date) 
+  (/ (- (calendar-absolute-from-gregorian date)

         (calendar-absolute-from-gregorian '(1 1.5 2000)))
      36525.0))
         (calendar-absolute-from-gregorian '(1 1.5 2000)))
      36525.0))

-  
+

 (defun solar-ephemeris-time(time)
   "Ephemeris Time at moment TIME.
 
 (defun solar-ephemeris-time(time)
   "Ephemeris Time at moment TIME.
 


@@ -520,7 +540,7 @@ calendar-time-zone are used to interpret local time."
         (setq end-long long)))
     (/ (+ start end) 2.0)))
 
         (setq end-long long)))
     (/ (+ start end) 2.0)))
 

-(defun solar-horizontal-coordinates 
+(defun solar-horizontal-coordinates

           (time latitude longitude for-sunrise-sunset)
   "Azimuth and height of the sun at TIME, LATITUDE, and LONGITUDE.
 
           (time latitude longitude for-sunrise-sunset)
   "Azimuth and height of the sun at TIME, LATITUDE, and LONGITUDE.
 


@@ -543,7 +563,7 @@ The azimuth is given in degrees as well as the height (between -180 and 180)."
                                 (* (solar-tangent-degrees de)
                                    (solar-cosine-degrees latitude)))
                               (solar-sin-degrees ah)))
                                 (* (solar-tangent-degrees de)
                                    (solar-cosine-degrees latitude)))
                               (solar-sin-degrees ah)))

-         (height (solar-arcsin 
+         (height (solar-arcsin

                   (+ (* (solar-sin-degrees latitude) (solar-sin-degrees de))
                      (* (solar-cosine-degrees latitude)
                         (solar-cosine-degrees de)
                   (+ (* (solar-sin-degrees latitude) (solar-sin-degrees de))
                      (* (solar-cosine-degrees latitude)
                         (solar-cosine-degrees de)


@@ -559,7 +579,7 @@ elapsed at 0 Universal Time, and the second component being the universal
 time.  For instance, the pair corresponding to November 28, 1995 at 16 UT is
 \(-0.040945 16), -0.040945 being the number of julian centuries elapsed between
 Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT."
 time.  For instance, the pair corresponding to November 28, 1995 at 16 UT is
 \(-0.040945 16), -0.040945 being the number of julian centuries elapsed between
 Jan 1, 2000 at 12 UT and November 28, 1995 at 0 UT."

-   (let* ((tm (solar-ephemeris-time time)) 
+   (let* ((tm (solar-ephemeris-time time))

           (ec (solar-ecliptic-coordinates tm for-sunrise-sunset)))
      (list (solar-right-ascension (car ec) (car (cdr ec)))
            (solar-declination (car ec) (car (cdr ec))))))
           (ec (solar-ecliptic-coordinates tm for-sunrise-sunset)))
      (list (solar-right-ascension (car ec) (car (cdr ec)))
            (solar-declination (car ec) (car (cdr ec))))))


@@ -571,16 +591,16 @@ at moment `time', expressed in julian centuries of Ephemeris Time
 since January 1st, 2000, at 12 ET."
   (let* ((l (+ 280.46645
                (* 36000.76983 time)
 since January 1st, 2000, at 12 ET."
   (let* ((l (+ 280.46645
                (* 36000.76983 time)

-               (* 0.0003032 time time))) ; sun mean longitude 
+               (* 0.0003032 time time))) ; sun mean longitude

          (ml (+ 218.3165
          (ml (+ 218.3165

-                (* 481267.8813 time))) ; moon mean longitude 
+                (* 481267.8813 time))) ; moon mean longitude

          (m (+ 357.52910
                (* 35999.05030 time)
                (* -0.0001559 time time)
          (m (+ 357.52910
                (* 35999.05030 time)
                (* -0.0001559 time time)

-               (* -0.00000048 time time time))) ; sun mean anomaly 
+               (* -0.00000048 time time time))) ; sun mean anomaly

          (i (+ 23.43929111 (* -0.013004167 time)
                (* -0.00000016389 time time)
          (i (+ 23.43929111 (* -0.013004167 time)
                (* -0.00000016389 time time)

-               (* 0.0000005036 time time time))); mean inclination 
+               (* 0.0000005036 time time time))); mean inclination

          (c (+ (* (+ 1.914600
                      (* -0.004817 time)
                      (* -0.000014 time time))
          (c (+ (* (+ 1.914600
                      (* -0.004817 time)
                      (* -0.000014 time time))


@@ -588,8 +608,8 @@ since January 1st, 2000, at 12 ET."
                (* (+ 0.019993 (* -0.000101 time))
                   (solar-sin-degrees (* 2 m)))
                (* 0.000290
                (* (+ 0.019993 (* -0.000101 time))
                   (solar-sin-degrees (* 2 m)))
                (* 0.000290

-                  (solar-sin-degrees (* 3 m))))) ; center equation 
-         (L (+ l c)) ; total longitude 
+                  (solar-sin-degrees (* 3 m))))) ; center equation
+         (L (+ l c)) ; total longitude

          (omega (+ 125.04
                    (* -1934.136 time))) ; longitude of moon's ascending node
                                         ; on the ecliptic
          (omega (+ 125.04
                    (* -1934.136 time))) ; longitude of moon's ascending node
                                         ; on the ecliptic


@@ -610,13 +630,13 @@ since January 1st, 2000, at 12 ET."
                  (* -0.00478
                     (solar-sin-degrees omega)))) ; apparent longitude of sun
          (y (if (not for-sunrise-sunset)
                  (* -0.00478
                     (solar-sin-degrees omega)))) ; apparent longitude of sun
          (y (if (not for-sunrise-sunset)

-                 (* (solar-tangent-degrees (/ i 2)) 
+                 (* (solar-tangent-degrees (/ i 2))

                   (solar-tangent-degrees (/ i 2)))
                 nil))
          (time-eq (if (not for-sunrise-sunset)
                     (/ (* 12 (+ (* y (solar-sin-degrees (* 2 l)))
                      (* -2 ecc (solar-sin-degrees m))
                   (solar-tangent-degrees (/ i 2)))
                 nil))
          (time-eq (if (not for-sunrise-sunset)
                     (/ (* 12 (+ (* y (solar-sin-degrees (* 2 l)))
                      (* -2 ecc (solar-sin-degrees m))

-                     (* 4 ecc y (solar-sin-degrees m) 
+                     (* 4 ecc y (solar-sin-degrees m)

                                 (solar-cosine-degrees (* 2 l)))
                      (* -0.5 y y  (solar-sin-degrees (* 4 l)))
                      (* -1.25 ecc ecc (solar-sin-degrees (* 2 m)))))
                                 (solar-cosine-degrees (* 2 l)))
                      (* -0.5 y y  (solar-sin-degrees (* 4 l)))
                      (* -1.25 ecc ecc (solar-sin-degrees (* 2 m)))))


@@ -625,48 +645,6 @@ since January 1st, 2000, at 12 ET."
                   ; equation of time, in hours
     (list app i time-eq nut)))
 
                   ; equation of time, in hours
     (list app i time-eq nut)))
 

-(defun solar-longitude (d)
-  "Longitude of sun on astronomical (Julian) day number D.
-Accurary is about 0.0006 degree (about 365.25*24*60*0.0006/360 = 1 minutes).
-
-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 are used to interpret local time."
-  (let* ((a-d (calendar-absolute-from-astro d))
-         ;; get Universal Time
-         (date (calendar-astro-from-absolute
-                (- a-d
-                   (if (dst-in-effect a-d)
-                       (/ calendar-daylight-time-offset 24.0 60.0) 0)
-                   (/ calendar-time-zone 60.0 24.0))))
-         ;; get Ephemeris Time
-         (date (+ date (solar-ephemeris-correction
-                        (extract-calendar-year
-                         (calendar-gregorian-from-absolute
-                          (floor
-                           (calendar-absolute-from-astro
-                            date)))))))
-         (U (/ (- date 2451545) 3652500))
-         (longitude
-          (+ 4.9353929
-             (* 62833.1961680 U)
-             (* 0.0000001
-                (apply '+
-                       (mapcar '(lambda (x)
-                                  (* (car x)
-                                     (sin (mod
-                                           (+ (car (cdr x))
-                                              (* (car (cdr (cdr x))) U))
-                                           (* 2 pi)))))
-                               solar-data-list)))))
-         (aberration
-          (* 0.0000001 (- (* 17 (cos (+ 3.10 (* 62830.14 U)))) 973)))
-         (A1 (mod (+ 2.18 (* U (+ -3375.70 (* 0.36 U)))) (* 2 pi)))
-         (A2 (mod (+ 3.51 (* U (+ 125666.39 (* 0.10 U)))) (* 2 pi)))
-         (nutation (* -0.0000001 (+ (* 834 (sin A1)) (* 64 (sin A2))))))
-    (mod (radians-to-degrees (+ longitude aberration nutation)) 360.0)))
-

 (defconst solar-data-list
   '((403406 4.721964 1.621043)
     (195207 5.937458 62830.348067)
 (defconst solar-data-list
   '((403406 4.721964 1.621043)
     (195207 5.937458 62830.348067)


@@ -719,6 +697,48 @@ calendar-time-zone are used to interpret local time."
     (10 1.50 21463.25)
     (10 2.55 157208.40)))
 
     (10 1.50 21463.25)
     (10 2.55 157208.40)))
 

+(defun solar-longitude (d)
+  "Longitude of sun on astronomical (Julian) day number D.
+Accurary is about 0.0006 degree (about 365.25*24*60*0.0006/360 = 1 minutes).
+
+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 are used to interpret local time."
+  (let* ((a-d (calendar-absolute-from-astro d))
+         ;; get Universal Time
+         (date (calendar-astro-from-absolute
+                (- a-d
+                   (if (dst-in-effect a-d)
+                       (/ calendar-daylight-time-offset 24.0 60.0) 0)
+                   (/ calendar-time-zone 60.0 24.0))))
+         ;; get Ephemeris Time
+         (date (+ date (solar-ephemeris-correction
+                        (extract-calendar-year
+                         (calendar-gregorian-from-absolute
+                          (floor
+                           (calendar-absolute-from-astro
+                            date)))))))
+         (U (/ (- date 2451545) 3652500))
+         (longitude
+          (+ 4.9353929
+             (* 62833.1961680 U)
+             (* 0.0000001
+                (apply '+
+                       (mapcar '(lambda (x)
+                                  (* (car x)
+                                     (sin (mod
+                                           (+ (car (cdr x))
+                                              (* (car (cdr (cdr x))) U))
+                                           (* 2 pi)))))
+                               solar-data-list)))))
+         (aberration
+          (* 0.0000001 (- (* 17 (cos (+ 3.10 (* 62830.14 U)))) 973)))
+         (A1 (mod (+ 2.18 (* U (+ -3375.70 (* 0.36 U)))) (* 2 pi)))
+         (A2 (mod (+ 3.51 (* U (+ 125666.39 (* 0.10 U)))) (* 2 pi)))
+         (nutation (* -0.0000001 (+ (* 834 (sin A1)) (* 64 (sin A2))))))
+    (mod (radians-to-degrees (+ longitude aberration nutation)) 360.0)))
+

 (defun solar-ephemeris-correction (year)
   "Ephemeris time minus Universal Time during Gregorian year.
 Result is in days.
 (defun solar-ephemeris-correction (year)
   "Ephemeris time minus Universal Time during Gregorian year.
 Result is in days.


@@ -793,7 +813,7 @@ T0 must correspond to 0 hours UT."
           (nut-i (solar-ecliptic-coordinates et nil))
           (nut (car (cdr (cdr (cdr nut-i))))) ; nutation
           (i (car (cdr nut-i)))) ; inclination
           (nut-i (solar-ecliptic-coordinates et nil))
           (nut (car (cdr (cdr (cdr nut-i))))) ; nutation
           (i (car (cdr nut-i)))) ; inclination

-       (mod (+ (mod (+ mean-sid-time 
+       (mod (+ (mod (+ mean-sid-time

                     (/ (/ (* nut (solar-cosine-degrees i)) 15) 3600)) 24.0)
                24.0)
             24.0)))
                     (/ (/ (* nut (solar-cosine-degrees i)) 15) 3600)) 24.0)
                24.0)
             24.0)))


@@ -881,7 +901,7 @@ This function is suitable for execution in a .emacs file."
                        "Type \\[delete-other-windows] to remove temp window."
                      "Type \\[switch-to-buffer] RET to remove temp window.")
                  "Type \\[switch-to-buffer-other-window] RET to restore old contents of temp window."))))))
                        "Type \\[delete-other-windows] to remove temp window."
                      "Type \\[switch-to-buffer] RET to remove temp window.")
                  "Type \\[switch-to-buffer-other-window] RET to restore old contents of temp window."))))))

- 
+

 (defun calendar-sunrise-sunset ()
   "Local time of sunrise and sunset for date under cursor.
 Accurate to a few seconds."
 (defun calendar-sunrise-sunset ()
   "Local time of sunrise and sunset for date under cursor.
 Accurate to a few seconds."


@@ -900,23 +920,62 @@ Accurate to a few seconds."
       (solar-setup))
   (solar-sunrise-sunset-string date))
 
       (solar-setup))
   (solar-sunrise-sunset-string date))
 

-(defun diary-sabbath-candles ()
+(defcustom diary-sabbath-candles-minutes 18
+  "*Number of minutes before sunset for sabbath candle lighting."
+  :group 'diary
+  :type 'integer
+  :version "21.1")
+
+(defun diary-sabbath-candles (&optional mark)

   "Local time of candle lighting diary entry--applies if date is a Friday.
   "Local time of candle lighting diary entry--applies if date is a Friday.

-No diary entry if there is no sunset on that date."
+No diary entry if there is no sunset on that date.
+
+An optional parameter MARK specifies a face or single-character string to
+use when highlighting the day in the calendar."

   (if (not (and calendar-latitude calendar-longitude calendar-time-zone))
       (solar-setup))
   (if (= (% (calendar-absolute-from-gregorian date) 7) 5);;  Friday
       (let* ((sunset (car (cdr (solar-sunrise-sunset date))))
   (if (not (and calendar-latitude calendar-longitude calendar-time-zone))
       (solar-setup))
   (if (= (% (calendar-absolute-from-gregorian date) 7) 5);;  Friday
       (let* ((sunset (car (cdr (solar-sunrise-sunset date))))

-                  (light (if sunset
-                        (cons (- (car sunset) (/ 18.0 60.0)) (cdr sunset)))))
+             (light (if sunset
+                        (cons (- (car sunset)
+                                 (/ diary-sabbath-candles-minutes 60.0))
+                              (cdr sunset)))))

         (if sunset
         (if sunset

-            (format "%s Sabbath candle lighting"
-                    (apply 'solar-time-string light))))))
+            (cons mark
+                 (format "%s Sabbath candle lighting"
+                    (apply 'solar-time-string light)))))))
+
+; from Meeus, 1991, page 167
+(defconst solar-seasons-data
+  '((485 324.96 1934.136)
+    (203 337.23 32964.467)
+    (199 342.08 20.186)
+    (182 27.85 445267.112)
+    (156 73.14 45036.886)
+    (136 171.52 22518.443)
+    (77 222.54 65928.934)
+    (74 296.72 3034.906)
+    (70 243.58 9037.513)
+    (58 119.81 33718.147)
+    (52 297.17 150.678)
+    (50 21.02 2281.226)
+    (45 247.54 29929.562)
+    (44 325.15 31555.956)
+    (29 60.93 4443.417)
+    (18 155.12 67555.328)
+    (17 288.79 4562.452)
+    (16 198.04 62894.029)
+    (14 199.76 31436.921)
+    (12 95.39 14577.848)
+    (12 287.11 31931.756)
+    (12 320.81 34777.259)
+    (9 227.73 1222.114)
+    (8 15.45 16859.074)))

 
 (defun solar-equinoxes/solstices (k year)
   "Date of equinox/solstice K for YEAR.
 K=0, spring equinox; K=1, summer solstice; K=2, fall equinox;
 
 (defun solar-equinoxes/solstices (k year)
   "Date of equinox/solstice K for YEAR.
 K=0, spring equinox; K=1, summer solstice; K=2, fall equinox;

-K=3, winter solstice. 
+K=3, winter solstice.

 RESULT is a gregorian local date.
 
 Accurate to less than a minute between 1951 and 2050."
 RESULT is a gregorian local date.
 
 Accurate to less than a minute between 1951 and 2050."


@@ -925,13 +984,13 @@ Accurate to less than a minute between 1951 and 2050."
          (W (- (* 35999.373 T) 2.47))
          (Delta-lambda (+ 1 (* 0.0334 (solar-cosine-degrees W))
                             (* 0.0007 (solar-cosine-degrees (* 2 W)))))
          (W (- (* 35999.373 T) 2.47))
          (Delta-lambda (+ 1 (* 0.0334 (solar-cosine-degrees W))
                             (* 0.0007 (solar-cosine-degrees (* 2 W)))))

-         (S (apply '+ (mapcar '(lambda(x) 
-                                 (* (car x) (solar-cosine-degrees 
+         (S (apply '+ (mapcar '(lambda(x)
+                                 (* (car x) (solar-cosine-degrees

                                              (+ (* (car (cdr (cdr x))) T)
                                              (+ (* (car (cdr (cdr x))) T)

-                                                  (car (cdr x)))))) 
+                                                  (car (cdr x))))))

                               solar-seasons-data)))
          (JDE (+ JDE0 (/ (* 0.00001 S) Delta-lambda)))
                               solar-seasons-data)))
          (JDE (+ JDE0 (/ (* 0.00001 S) Delta-lambda)))

-         (correction (+ 102.3 (* 123.5 T) (* 32.5 T T))) 
+         (correction (+ 102.3 (* 123.5 T) (* 32.5 T T)))

              ; ephemeris time correction
          (JD (- JDE (/ correction 86400)))
          (date (calendar-gregorian-from-absolute (floor (- JD 1721424.5))))
              ; ephemeris time correction
          (JD (- JDE (/ correction 86400)))
          (date (calendar-gregorian-from-absolute (floor (- JD 1721424.5))))


@@ -943,7 +1002,7 @@ Accurate to less than a minute between 1951 and 2050."
 
 ; from Meeus, 1991, page 166
 (defun solar-mean-equinoxes/solstices (k year)
 
 ; from Meeus, 1991, page 166
 (defun solar-mean-equinoxes/solstices (k year)

-  "Julian day of mean equinox/solstice K for YEAR.  
+  "Julian day of mean equinox/solstice K for YEAR.

 K=0, spring equinox; K=1, summer solstice; K=2, fall equinox; K=3, winter
 solstice.  These formulas are only to be used between 1000 BC and 3000 AD."
   (let ((y (/ year 1000.0))
 K=0, spring equinox; K=1, summer solstice; K=2, fall equinox; K=3, winter
 solstice.  These formulas are only to be used between 1000 BC and 3000 AD."
   (let ((y (/ year 1000.0))


@@ -991,33 +1050,6 @@ solstice.  These formulas are only to be used between 1000 BC and 3000 AD."
                                    (* -0.00823 z z z)
                                    (* 0.00032 z z z z)))))))
 
                                    (* -0.00823 z z z)
                                    (* 0.00032 z z z z)))))))
 

-; from Meeus, 1991, page 167
-(defconst solar-seasons-data
-  '((485 324.96 1934.136)
-    (203 337.23 32964.467)
-    (199 342.08 20.186)
-    (182 27.85 445267.112)
-    (156 73.14 45036.886)
-    (136 171.52 22518.443)
-    (77 222.54 65928.934)
-    (74 296.72 3034.906)
-    (70 243.58 9037.513)
-    (58 119.81 33718.147)
-    (52 297.17 150.678)
-    (50 21.02 2281.226)
-    (45 247.54 29929.562)
-    (44 325.15 31555.956)
-    (29 60.93 4443.417)
-    (18 155.12 67555.328)
-    (17 288.79 4562.452)
-    (16 198.04 62894.029)
-    (14 199.76 31436.921)
-    (12 95.39 14577.848)
-    (12 287.11 31931.756)
-    (12 320.81 34777.259)
-    (9 227.73 1222.114)
-    (8 15.45 16859.074)))
-

 ;;;###autoload
 (defun solar-equinoxes-solstices ()
   "*local* date and time of equinoxes and solstices, if visible in the calendar window.
 ;;;###autoload
 (defun solar-equinoxes-solstices ()
   "*local* date and time of equinoxes and solstices, if visible in the calendar window.


@@ -1035,13 +1067,14 @@ Requires floating point."
             (if calendar-time-zone calendar-daylight-savings-ends))
            (calendar-time-zone (if calendar-time-zone calendar-time-zone 0))
            (k (1- (/ m 3)))
             (if calendar-time-zone calendar-daylight-savings-ends))
            (calendar-time-zone (if calendar-time-zone calendar-time-zone 0))
            (k (1- (/ m 3)))

-           (d0 (solar-equinoxes/solstices k y)) 
+           (d0 (solar-equinoxes/solstices k y))

            (d1 (list (car d0) (floor (car (cdr d0))) (car (cdr (cdr d0)))))
            (h0 (* 24 (- (car (cdr d0)) (floor (car (cdr d0))))))
            (adj (dst-adjust-time d1 h0))
            (d1 (list (car d0) (floor (car (cdr d0))) (car (cdr (cdr d0)))))
            (h0 (* 24 (- (car (cdr d0)) (floor (car (cdr d0))))))
            (adj (dst-adjust-time d1 h0))

-           (d (list (car d1) (+ (car (cdr d1))  
-                  (/ (car (cdr adj)) 24.0))
-                    (car (cdr (cdr d1)))))
+           (d (list (car (car adj))
+                    (+ (car (cdr (car adj))  )
+                       (/ (car (cdr adj)) 24.0))
+                    (car (cdr (cdr (car adj))))))

            ; The following is nearly as accurate, but not quite:
           ;(d0 (solar-date-next-longitude
            ;    (calendar-astro-from-absolute
            ; The following is nearly as accurate, but not quite:
           ;(d0 (solar-date-next-longitude
            ;    (calendar-astro-from-absolute


@@ -1066,4 +1099,5 @@ Requires floating point."
 
 (provide 'solar)
 
 
 (provide 'solar)
 

+;;; arch-tag: bc0ff693-df58-4666-bde4-2a7837ccb8fe

 ;;; solar.el ends here
 ;;; solar.el ends here