HTOOL is simple application to query for Horizons ephemeris data and issue NEXT or NS.RATE (nonsidereal rates) command to TCS3.

1. Before using htool you will need the target ID for your object.

Major Bodies - Planets, natural satellites, or the Sum
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).

Small Bodies - coment 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.

Comets

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.

2. To start htool, login into an IRTF workstation (ie max or stefan) and type 'htool' in an xterm, or terminal window.

3. Sending NEXT object or NS.RATE commands to tcs3. At the htool prompt:

Use 't' to specify your target.
Use 'q' to query horizon for data. (It should show you a summary of the data).
Use 'n' to issue a NEXT command to the tcs3 (Slew immediately after 'n').
Use 'r' to issue a NS.RATE command to tcs3.
Type 'help' to list all the commands.

Also, typing in a 'target ID' at the command prompt will specify the target and do a query.

4. It a good ideal to be familiar with using Horizons.

References

major_body.html Major Body Cheat Sheet
Horizons Web Site
Horizons Documentation as PDF (local copy)
Using a Horizon generated text files as input to HTOOL