Hi Antonio,

Guide does some pretty strange "markup language"-type things here.
They are used in the help system, event lists, Quick Info, and some
other places.

Back when I first wrote Guide, it had a simple 'help' system in which
I could define glossary terms. If you click on, say, Sirius, and ask
for "More Info", Guide creates a file 'temphelp.txt' that begins with:

Comments from the ^Hipparcos^ Catalog:

The carets (^) tell Guide that "Hipparcos" is a glossary term; it
should be displayed in blue, and if the user clicks on it, Guide
should look for the glossary entry for Hipparcos in 'help.txt'. (Or
in 'ihelp.txt' for Italian, 'fhelp.txt' for French, and so on.)

Much later, I decided that it would be very useful if the link
could be, not to a glossary term, but to some sort of action in Guide.
In such cases, the highlighted term starts with a caret, is followed
by //, then by something encoding the action, usually resetting the
time or telling Guide to center on a particular RA/dec or object.
For example,

Click here to center on ^M 1 //gr83.6329,22.0144^

would cause "M 1" to be highlighted; clicking on it would cause Guide
to go to RA=83.6329 degrees, dec = 22.0144 degrees.

Use 'Quick Info' and look at temphelp.txt, and you'll see this sort
of thing everywhere. For example, in the list of planets,

^Jupiter //ch5;gp05^ 23h23m49.86s -04 59' 02.8" ^09:53//j2455298.9119;gp5^

(I've clipped some extra junk), //ch5;gp05 means "if the user clicks
on 'Jupiter', then set help color 5 (usually green, meaning Jupiter is
above the horizon). Then gp05 means Guide should center on planet 5,
which happens to be Jupiter".

At the end of that line, //j2455298.9119;gp5 means "if the user clicks
on '09:53', set the time to JD 2455298.9119, the time that Jupiter rises,
i.e., 9:53. Then go to planet 5." So you can click on the rise or set
times, and see that planet rising or setting.

Other commands cause Guide to sort lists, download files (see 'tle.hee'
and 'add_mpc.hee'), start up the browser to show a particular Web page,
and so forth.

-- Bill