jday

Langue: en

Version: 148590 (fedora - 04/07/09)

Section: 1 (Commandes utilisateur)

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 © 1986-2005, Hiram Clawson
jday at hiram.ws
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