This function will convert a Julian
date number to a Gregorian calendar date string.
Sample usage:
wscript.echo jd2greg(2435605.92708)
Sample output:
5-12-1956 10:14:60
You can modify the output format
by changing the last line of the function.
' adapted from the function
jd_to_cal by Marc A. Murison
' Astronomical Applications Dept. U.S. Naval
Observatory
' 3450 Massachusetts Ave, NW Washington, DC
20392-5420
' http://aa.usno.navy.mil/data/docs/JulianDate.html
Function jd2greg(jd)
intgr = int(jd)
frac = jd - intgr
gregjd = 2299161
if(intgr >= gregjd) then
tmp = int(((intgr - 1867216) - 0.25) / 36524.25)
j1 = intgr + 1 + tmp - int(0.25*tmp)
else
j1 = intgr
end if
'correction for half day offset
dayfrac = frac + 0.5
if(dayfrac >= 1.0) then
dayfrac = dayfrac - 1
j1 = j1 + 1
end if
j2 = j1 + 1524
j3 = int(6680.0 + ((j2 - 2439870) - 122.1)/365.25)
j4 = int(j3*365.25)
j5 = int((j2 - j4)/30.6001)
d = int(j2 - j4 - int(j5*30.6001))
m = int(j5 - 1)
if(m > 12) then
m = m -12
end if
y = int(j3 - 4715)
if(m > 2) then
y = y -1
end if
if(y <= 0) then
y = y - 1
end if
' get time of day from day fraction
hr = int(dayfrac * 24.0)
mn = int((dayfrac*24.0 - hr)*60.0)
f = ((dayfrac*24.0 - hr)*60.0 - mn)*60.0
sc = int(f)
f = sc -1
if(f > 0.5) then
sc = sc + 1
end if
if(y < 0) then
y = -y
end if
jd2greg = m & "-" & d & "-" & y &
" " & hr & ":" & mn & ":" & sc
End Function |
|
