HTOOL - HORIZONS TOOL
1. HTOOL is simple application to query for JPL Horizons ephemeris data, and
issue NEXT or NS.RATE (nonsidereal rates) command to TCS3.
And updates rates to the guider.
To start htool, type 'htoolgui' in a terminal.
Here is the user's guide: htoolgui.pdf.
2. Before using htool you will need the target ID for your object.
Major Bodies - Planets, natural satellites, or the Sum
3. Importing Horizon data into HTOOL - Instructions on importing saved
Horizon output into HToolGUI.
You will need the JPL ID ( for example, 499 is Mars )
Used the web to query horizon for the JPL ID, use this
Major Body Cheat Sheet .
Or look here:
List of Major Body Ephemerides (JPL documentation).
Here is an example using Geodetic/planetodetic coordinates: g:E.long,latitude,h@BODY
g:348.8,-43.3,0@301 # The Moon at Log=348.8 Lat=-43.0, Alt=0
Small Bodies - comments or asteroids
Small bodies are enter the Record number following the ';'. For example
'1;' is Ceres (as oppose to '1' for venus).
Use the JPL web inteface to lookup the recorded number for your small body.
The preference would be to use the JPL records # with htool.
Asteroids with Numbers
For numbered asteroids (1 to 100000), enter the record # followed by ';'.
the record# is equal to the asteriod#, so '10000;' would be
'Asteroid 10000 Myriostos (1951 SY)'.
Asteroids with out Numbers
For an asteroid without a JPL record# use its name, for example '2008 AA1'
Note, the name are case senitive and have embedded spaces. Its best to
confirm the name via the web interface first, then use it in htool.
For comets, used Horizons find its Record #.
For example, for comet 27P:
1. The target body search yields 5 choices.
2. Select the more recent and generate the Ephemeris.
3. The Object Data Page provides the record#, in this case 900365.
major_body.html Major Body Cheat Sheet
Horizons Web Site
Horizons User Manual
Horizons Documentation as PDF (local copy)