Hello,
I think I have found bugs in the the CalDat procedure. I
thought it best to run it by here before contacting RSI.
This is from the online help:
> ... use something like:
> CALDAT, 2529161.36, Month, Day, Year, Hour, Minute, Second
> PRINT, Month, Day, Year, Hour, Minute, Second
>
Here are my observations:
1) Unless the Julian Day Number is double precision, the
minute and hour are always zero.
2) I don't believe the hour is correctly determing when
the Julian Day number is provided as single precision.
If the Julian Day begins at 1200 on a given day, then 0.36 *
24 + 12 = 20.6 (fraction of day * hours per day + offset =
hour number of day)
As single precision:
IDL> CALDAT, 2529161.36, Month, Day, Year, Hour, Minute,
Second
IDL> PRINT, Month, Day, Year, Hour, Minute, Second
7 4 2212 18
0 0.00000000
As double precision:
IDL> CALDAT, 2529161.36d, Month, Day, Year, Hour, Minute,
Second
IDL> PRINT, Month, Day, Year, Hour, Minute, Second
7 4 2212 20
38 23.999989
As long integer:
IDL> CALDAT, 2529161L, Month, Day, Year, Hour, Minute,
Second
IDL> PRINT, Month, Day, Year, Hour, Minute, Second
7 4 2212 12
0 0.00000000
I hope some folks will confirm this result on other machines
before I send along a bug report to RSI; perhaps this has
been noted before.
IDL> print, !version
{ x86 Win32 Windows 5.4 Sep 25 2000 32 64}
Thanks,
Ben
--
Ben Tupper
248 Lower Round Pond Road
POB 106
Bristol, ME 04539
Tel: (207) 563-1048
Email: PemaquidRiver@tidewater.net
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