Using NASA's JPL Solar System Dynamics site

Use NASA's Jet Propulsion Lab's (JPL) "Horizons" system to check any data:
If you need a new window for NASA's Horizon's system, click here:
NASA's Jet Proplulsion Laboratory "Horizon's" site.



1. Under 'Current Settings,' there are seven items:
            
            Ephemeris Type [change] :  
               Target Body [change] :  
         Observer Location [change] : 
                 Time Span [change] : 
            Table Settings [change] : 
            Display/Output [change] : 

2. Click '[change]', and set the options as described below:
            
            Ephemeris Type [change] : OBSERVER 
               Target Body [change] : {in the 'Look up the specified body' box enter '24 themis' w/o quotes}
         Observer Location [change] : {in the 'Lookup Named Location' box enter 'Geocentric' or '500' w/o quotes}
                 Time Span [change] : {enter the time frame you want}
            Table Settings [change] : {first click the 'none' button, then check only '* 31. Obs eclip. lon & lat'}
            Display/Output [change] : 

   NOTE: Each 'change' will require that a button specific to the change is clicked after the data choice is made:

            Ephemeris Type [change] : click 'Observer Table' radio button
               Target Body [change] : click the 'Search' button after entering '24 themis'
         Observer Location [change] : click the 'Search' button after entering 'Geocentric' or '500'
                 Time Span [change] : click the 'Use Specified Times' button after entering your dates/times 
            Table Settings [change] : click 'Use Settings Below' Button after checking only '* 31. Obs eclip. lon & lat'
            Display/Output [change] : click 'Use Selection Above' after selecting your choice (usually 'HTML (default)')


   Finally, after all selctions are made, click the 'Generate Ephemeris' button, and you will get a page with much data.
  
   Half way down the new page will be a section formatted like the following:

   Date__(UT)__HR:MN        ObsEcLon    ObsEcLat
  **********************************************
  $$SOE                                          
   1941-Dec-01 00:00     177.9900428   0.6191893  
   1941-Dec-02 00:00     178.2947658   0.6203720  
   1941-Dec-03 00:00     178.5967665   0.6215694  
   1941-Dec-04 00:00     178.8959978   0.6227816  
   1941-Dec-05 00:00     179.1924095   0.6240086  
   1941-Dec-06 00:00     179.4859494   0.6252504  
   1941-Dec-07 00:00     179.7765630   0.6265068  
   1941-Dec-08 00:00     180.0641940   0.6277777  
   1941-Dec-09 00:00     180.3487848   0.6290626  
   1941-Dec-10 00:00     180.6302769   0.6303610  
   1941-Dec-11 00:00     180.9086118   0.6316722  
   1941-Dec-12 00:00     181.1837304   0.6329956  
   1941-Dec-13 00:00     181.4555743   0.6343301  
   1941-Dec-14 00:00     181.7240849   0.6356750  
   1941-Dec-15 00:00     181.9892030   0.6370290  
  $$EOE
  **********************************************

  The values under the column 'ObsEcLon' (Observer Ecliptic Longitude)
  correspond to the type of data used in our graphs, and is also the
  standard data reference for tropical zodiac positions.

  Now you can see from the above that NASA's data and the data in the
  graph is essentially identical.

  Use your browser's 'Back' button to return to the start if you want
  to compare any other data.

  If you want to open up a full browser window and save a bookmark for
  HORIZONs, the link is here:NASA's Jet Proplulsion Laboratory "Horizons" site.