Wobble Tracker is a shareware program that enables you
to see Chandler's Wobble on a 2-D chart. The purpose of this is so that you can view the
wobble and see how much drift the pole position is undergoing, along with the direction of
the drift. All data included with Wobble Tracker is publicly available from the IERS Web
site (www.iers.org), and the Wobble Tracker has the functionality built in to download the
latest wobble data so that you can keep up-to-date on the state of the pole position. The
X+ line is the Greenwich meridian. The Y+ line is on the 90-degree West meridian, passing
through North America.
This application was created for the use of individuals
for monitoring the current state of Chandler's Wobble. It is intended to enable the user
to see the direction and amount of drift has taken place in the location of the pole over
For technical support, registered buyers can send an
This application has been tested on Windows 2000 and NT
4. It has not been tested on any other Microsoft operating system. If it does not run on
your OS, please send an e-mail to the above address, specifying the OS you are running,
and a description of the problem you are encountering.
To connect with a user group, send a blank email
message addressed to:
Displaying Wobble Data
To display daily wobble data starting with 1962, select
the year from the drop-down box labeled "Year To Draw". To draw all daily data,
at the bottom of this list is an option for "ALL." Selecting this option will
draw all of the daily wobble data starting with 1962.
To draw historical wobble data from 1846 to 1961,
select the year from the drop-down box labeled "Historical Year To Draw" and
select the number of sequential years to draw from the drop-down box labeled "Number
of Years To Draw." Historical data from 1846 to 1889 contains only 10 data points per
year. Starting in 1890 through 1961 there are 20 data points per year.
The Draw menu provides options for selecting a color to
draw for any years specified after selecting the color. This menu also contains and option
to specify the line width to be used when drawing the wobble data. The final option on
this menu will clear the current drawing.
The View menu provides options for turning the grid
display on and off, along with configuring the scale of the grid, and the scale of the
wobble data display. In general, the best settings for the drawing scale are 0.7 to 0.6
range. The default setting for the grid is 0.05, which draws the grid lines at 1/20
arc-seconds, which is slightly more than 5 feet, or a little over 1.5 meters.
A chart of grid settings and their equivalent distances
in included in a Readme.txt file, along with all of these instructions.
The File menu provides options for specifying the
location of the data files containing the wobble data. By default, this is initialized in
a directory called "data" directly below the directory where the Wobble Tracker
application has been installed. Another option on the File menu, labeled "Get Data
Update" will download the latest daily data file for the current year from the IERS
web site and install the data file in the data directory.