; beginning of Julian dates
       0    -4713  1  1 Mon   0
       1    -4713  1  2 Tue   1
       2    -4713  1  3 Wed   2
       3    -4713  1  4 Thu   3
;
; Julian calendar repeats every 4 years, at 365*4+1 = 1461 day intervals
  260424    -4000  1  1 Thu   0
;   1461        4
  261885    -3996  1  1 Tue   0
;   1461        4
  263346    -3992  1  1 Sun   0
;
; Julian dates near 1 AD (there was no year 0)
 1721420       -1 12 28 Tue 362
 1721421       -1 12 29 Wed 363
 1721422       -1 12 30 Thu 364
 1721423       -1 12 31 Fri 365
 1721424        1  1  1 Sat   0
 1721425        1  1  2 Sun   1
 1721426        1  1  3 Mon   2
;
;	usual transition dates are:
;
;	2299161 = October 5/15, 1582,       as in Rome, or
;	2361222 = September 3/14, 1752,     as in the United Kingdom 
;	                                    and the Colonies (default)
;
; Julian dates near the transition...
;          
 2361220       1752  9  1  Tue  244 
 2361221       1752  9  2  Wed  245 
 2361222       1752  9 14  Thu  246 
 2361223       1752  9 15  Fri  247 
T2299161                                ; as in Rome
 2299159     1582 10  3 Wed 275
 2299160     1582 10  4 Thu 276
 2299161     1582 10 15 Fri 277
 2299162     1582 10 16 Sat 278
;
; Apart from the 4000 year correction, the Gregorian calendar repeats 
; every 400 years, or at ((365*4+1)*25-1)*4+1 = 146097 day intervals
 2302526     1592  1  1 Wed   0
; 146097      400
 2448623     1992  1  1 Wed   0
; 146097      400
 2594720     2392  1  1 Wed   0
; 146097      400
 2740817     2792  1  1 Wed   0
;
; Including the 4000 year correction, the Gregorian calendar repeats 
; at (((365*4+1)*25-1)*4+1)*10-1 = 1460969 day intervals
 2302526     1592  1  1 Wed   0
;1460969     4000
 3763495     5592  1  1 Tue   0
;1460969     4000
 5224464     9592  1  1 Mon   0
;1460969     4000
 6685433    13592  1  1 Sun   0
;
;	The USNO time service reports the Modified Julian Date (MJD),
;	which is figured by subtracting a constant (2,400,000.5) from the
;	Julian Date as of the preceding midnight.
;
;    For example, the MJD for 7 Jul 92 was 48806
;                              offset    2400000.5
;                     JD at midnight was 2448806.5
;                         JD at noon was 2448807
;
 2448807     1992  7  3 Fri 184
;
; checks on day-of-week calculation...
; "black Tuesday" 
 2425914     1929 10 29 Tue 301
; "a day that will live in infamy"
 2430336     1941 12  7 Sun 340
; "black Monday" 
 2447088     1987 10 19 Mon 291
