Select departure city by using mouse (click on the map) or select
a predefined city from the pull-down menu. Vertical
blue line on the map indicates
your departure selection.
Press From/To button and select the destination city
(indicated by vertical red line).
The result shown in the lower right-hand corner tells the sun exposure
start time (0h-23h) in your departure time zone clock.
This is the time when you should go outside and enjoy
bright sunlight for an hour or two
in order to reset your body clock. This helps you to adapt into
new inner rhythm at new timezone.
In order to find the sun exposure time for your return trip,
press Direction and read the new result.
If you know the airport codes of your departure and destination
cities, (e.g. CDG for Paris Charles de Gaulle),
you can use
different user interface.
The idea of this programming exercice is based on the deleter
manual, which can be found from
This is also the right place for comments on the applet code.
Sadly, Art Winfree is no longer among us.
His work lives here in code and science.
The virtual location of this page is
here but mostly you are better off by using the actual
Make sure that both files are located in the same directory.
Point your browser to JetLagDeleter.html - that's all.
Command line usage
% java -jar JetLagDeleter.jar HEL NRT
Recommended sun exposure start time is 02:12 at your departure city time.
Copying policy and non-warranty
JetLagDeleter - calculate body clock reset time
Copyright (C) 1999-2002 Arthur Winfree and Petteri Kettunen
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA