;Dates of the form YYYYMMDD may be packed into five characters to conserve space.
;The first two digits of the year are packed into a single character in column 1 (I = 18, J = 19, K = 20). Columns 2-3 contain the last two digits of the year. Column 4 contains the month and column 5 contains the day, coded as detailed below:
;
;   Month     Day      Character         Day      Character
;                     in Col 4 or 5              in Col 4 or 5
;   Jan.       1           1             17           H
;   Feb.       2           2             18           I
;   Mar.       3           3             19           J
;   Apr.       4           4             20           K
;   May        5           5             21           L
;   June       6           6             22           M 
;   July       7           7             23           N
;   Aug.       8           8             24           O 
;   Sept.      9           9             25           P
;   Oct.      10           A             26           Q
;   Nov.      11           B             27           R
;   Dec.      12           C             28           S
;             13           D             29           T
;             14           E             30           U
;             15           F             31           V
;             16           G            
;
;Examples:
;
;   1996 Jan. 1    = J9611
;   1996 Jan. 10   = J961A
;   1996 Sept.30   = J969U
;   1996 Oct. 1    = J96A1
;   2001 Oct. 22   = K01AM
;This system can be extended to dates with non-integral days. The decimal fraction of the day is simply appended to the five characters defined above.
;Examples:
;
;   1998 Jan. 18.73     = J981I73
;   2001 Oct. 22.138303 = K01AM138303

function unpack_mpcepoch, estr, yr, mo, dy

    centstr = strmid(estr,0,1)
    yrstr = strmid(estr,1,2)
    mostr = strmid(estr,3,1)
    dystr = strmid(estr,4,1)

    yr = (byte(centstr)-byte('I')+18)*100 + fix(yrstr)
    a = byte('A')
    if byte(mostr) lt a then mo = fix(mostr) else mo = byte(mostr)-a+10
    if byte(dystr) lt a then dy = fix(dystr) else dy = byte(dystr)-a+10

    return, string(yr, mo, dy, form='(I4,"/",I2.2,"/",I2.2)')
    
end