nasa horizons

NASA Horizons

No, I'm not talking about the New Horizons satellite. I'm talking

about a service that has been done by NASA (specifically JPL) since at

least 1996. This is just called "Horizons" (no "new"). This is a

service provided by JPL that provides information for several

(thousand) Solar System objects, including Ephemeris(es?) and basic

geologic information. Now, I'll show you how to use the Horizons

service with ease (actually it's not very easy, but it's useful). This

is done by an internet protocol called Telnet. Telnet basically allows

you to get into other computers over the internet. Now, there have

been a couple of stories about Telnet being highly insecure, but if

you're only using it for the Horizons service, then I think it's

pretty safe. If you use it for other, more private, matters, you might

want to use ssh (I'll go over this once I learn more about it).

First, get Telnet. This is usually not needed for most computers. If

you have Windows, you can either use the out-of-the-box Hyperterminal

or get some fancy-schmancy program I have no clue about. I will give

instructions via the Hyperterminal. If you have linux, as I do, your

computer should already have Telnet, but disabled. See the

documentation for your specific distribution to find out how to enable

it. The next 3 steps will be for Windows users, linux users could skip

down.

Second, open the Hyperterminal. If you have Windows XP, you go All

Programs> Accessories> Communications> Hyperterminal. If you have a

previous version of Windows, you go Programs> Accessories>

Communications> Hyperterminal.

Third, name your connection. This is a rather free step. Just name it

whatever you want and click next.

Fourth, set up your connection. Now, for Telnet, you do not use the

COM1, or whatever item you see in the last drop-down box. You click on

that box and change it to TCP/IP (Windsock). Now, for the address, you

put in horizons.jpl.nasa.gov and for the port you put in 6775. Click

next and you're connected. Hooray.

Linux users, your job in considerably easier. Just open up the

terminal and type "telnet horizons.jpl.nasa.gov 6775". Now you're