phases-of-moon did not include fix for change of julian/gregorian calendar for dates < 15-OCT-1582

phases-of-moon did not include fix for change of julian/gregorian calendar for dates < 15-OCT-1582

[Frank Scherie]

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Hello,

trying to figure out lunar phase for 26-APR-1336 gives in emacs using

--------------------------------------
C-u M-x phase-o-moon
Year: 1336
Month: April

Thursday, March 22, 1336: New Moon 1:37am (CET)
Wednesday, March 28, 1336: First Quarter Moon 8:55pm (CEST)
Thursday, April 5, 1336: Full Moon 2:54am (CEST)
Friday, April 13, 1336: Last Quarter Moon 5:34am (CEST)
Friday, April 20, 1336: New Moon 12:48pm (CEST)
Friday, April 27, 1336: First Quarter Moon 3:28am (CEST)
Friday, May 4, 1336: Full Moon 5:39pm (CEST)
Saturday, May 12, 1336: Last Quarter Moon 9:22pm (CEST)
Saturday, May 19, 1336: New Moon 8:44pm (CEST)
Saturday, May 26, 1336: First Quarter Moon 11:26am (CEST)
--------------------------------------

while NASA 6000 Year lunar phase table gives for 1301-1400 
<http://sunearth.gsfc.nasa.gov/eclipse/phase/phases1301.html>

--------------------------------------

 Year      New Moon       First Quarter       Full Moon       Last Quarter          ?T


 1336                                                         Jan  6  15:37      00h07m
        Jan 14  19:52     Jan 22  04:59     Jan 28  22:06     Feb  5  12:21    
        Feb 13  11:35     Feb 20  12:29     Feb 27  10:56     Mar  6  08:49    
        Mar 14  00:31 H   Mar 20  18:50     Mar 28  00:54 n   Apr  5  03:24    
        Apr 12  10:42     Apr 19  01:23     Apr 26  15:39     May  4  19:12    
        May 11  18:39     May 18  09:22     May 26  06:43     Jun  3  07:52    
        Jun 10  01:20     Jun 16  19:41     Jun 24  21:42     Jul  2  17:34    
        Jul  9  07:59     Jul 16  08:49     Jul 24  12:20     Aug  1  00:54    
        Aug  7  15:51     Aug 15  00:48     Aug 23  02:24     Aug 30  06:53    
        Sep  6  01:57 H   Sep 13  19:13     Sep 21  15:36 n   Sep 28  12:50    
        Oct  5  14:54     Oct 13  15:12     Oct 21  03:47     Oct 27  20:09    
        Nov  4  06:44     Nov 12  11:17     Nov 19  15:04     Nov 26  06:02    
        Dec  4  00:54     Dec 12  05:39     Dec 19  01:47     Dec 25  19:01    

----------------------------------------

Looks like "phases-of-moon" does not calculate julian/gregorian calendar 
switch -
i.e. when date is earlier then 15 Oktober 1582 which is first date of
gregorian calendar.

emacs
----------------------------------------
Saturday, August 28, 1582: New Moon 7:54am (CEST)
Sunday, September 5, 1582: First Quarter Moon 11:49am (CEST)
Sunday, September 12, 1582: Full Moon 2:20pm (CEST)
Sunday, September 19, 1582: Last Quarter Moon 4:56am (CEST)
Sunday, September 26, 1582: New Moon 11:35pm (CEST)
Tuesday, October 5, 1582: First Quarter Moon 3:27am (CEST)
Monday, October 11, 1582: Full Moon 10:56pm (CEST) 
~~~~~~~~~~~~~~~~~~ before 15-OCT-1582 results WRONG ~~~~~~~~~~
Monday, October 18, 1582: Last Quarter Moon 4:10pm (CEST)
Tuesday, October 26, 1582: New Moon 5:15pm (CEST)
----------------------------------------

NASA (1501-1600 
<http://sunearth.gsfc.nasa.gov/eclipse/phase/phases1501.html>)
----------------------------------------

 Year      New Moon       First Quarter       Full Moon       Last Quarter          ?T


 1582                     Jan  1  14:59     Jan  8  22:23 p   Jan 17  02:02      00h02m
        Jan 24  08:56     Jan 30  23:59     Feb  7  16:08     Feb 15  20:26    
        Feb 22  19:21     Mar  1  10:47     Mar  9  10:02     Mar 17  11:05    
        Mar 24  04:08     Mar 30  23:42     Apr  8  02:55     Apr 15  21:43    
        Apr 22  12:04     Apr 29  14:31     May  7  18:04     May 15  04:52    
        May 21  20:11     May 29  06:41     Jun  6  07:11 n   Jun 13  09:46    
        Jun 20  05:26 T   Jun 27  23:40     Jul  5  18:18 n   Jul 12  13:59    
        Jul 19  16:32     Jul 27  16:56     Aug  4  03:48     Aug 10  19:10    
        Aug 18  05:53     Aug 26  09:47     Sep  2  12:23     Sep  9  02:51    
        Sep 16  21:34     Sep 25  01:26     Oct  1  20:59     Oct 18  14:05    
        Oct 26  15:15     Nov  3  15:06     Nov 10  06:30     Nov 17  05:17    
        Nov 25  09:57     Dec  3  02:23     Dec  9  17:31 n   Dec 17  00:03    
        Dec 25  04:09 A     

----------------------------------------

cheers,
Frank Scherie


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Re: phases-of-moon did not include fix for change of julian/gregorian calendar for dates < 15-OCT-1582

[Edward M. Reingold]

>>>>> "FS" == Frank Scherie <frank.scherie@oracle.com> writes:

    FS> Hello, trying to figure out lunar phase for 26-APR-1336 gives in emacs

All dates are given on the Grgeorian calendar.  That is a feature, not a bug:
the adoption of the Gregorian calendar took place over many centuries, not all
at once as many people assume.


-- 

Professor Edward M. Reingold                Email: reingold@iit.edu
Department of Computer Science              Voice: (312) 567-3309
Illinois Institute of Technology            Fax:   (312) 567-5067
Stuart Building, 228F
10 West 31st Street
Chicago, IL  60616-3729  U.S.A.

Re: phases-of-moon did not include fix for change of julian/gregorian calendar for dates < 15-OCT-1582

[Richard Stallman]

    Looks like "phases-of-moon" does not calculate julian/gregorian calendar 
    switch -
    i.e. when date is earlier then 15 Oktober 1582 which is first date of
    gregorian calendar.

That is right.  You have to do that yourself.

This is documented in the manual, isn't it?