JDAY(1)

NAME
jday, j2d - astronomical julian date conversion utilities

SYNOPSIS
jday

jday [-d [-]year/mm/dd hh:mm:ss]

jday [--version]

jday [--h[elp]]

j2d <julian decimal date>

j2d [--version]

j2d [--h[elp]]

DESCRIPTION

jday and j2d are command line utilities to convert calendar dates to astronomical julian dates, and julian dates to calendar dates. There is a corresponding library libjday.a which can be used for the same functionality within applications.

OPTIONS
jday accepts the following options:

none at all
    jday will simply print out the julian date based on the date and time found on the system.

[year [month [day [hour [minute [second]]]]]]
    Always in that order, to override that value found on the system.

-d [-]year/mm/dd hh:mm:ss
    Specify a year in the same format as that printed out by j2d

j2d accepts the following options:

<julian decimal date>
    This is the only, and required argument to j2d

both commands accept the following options:

--version
    Display the version of the programs.

--h[elp]
    Display a command help message

EXAMPLES
$ jday 1970 1 1 12 0 0
2440588.000000
$ jday 0 1 1 12 0 0
1721058.000000
$ jday -4712 1 1 12 0 0
0.000000
$ jday -d -4712/01/01 12:00:00
0.000000
$ j2d 0.0
-4712/01/01 12:00:00
$ j2d 1721058.0
0/01/01 12:00:00
$ j2d 2440588.0
1970/01/01 12:00:00

SEE ALSO
Time Standard: http://tycho.usno.navy.mil
Systems of time: http://tycho.usno.navy.mil/systime.html

COPYRIGHT
Copyright © 1986-2002, Hiram Clawson

curator@hiram.ws.NoSpam

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