Hi Thomas,

This is because Guide is a bit more sophisticated in its
handling of the GRS longitude now:

http://www.projectpluto.com/update8d.htm#grs_setting

Quoting from the above URL:

"The Great Red Spot longitude is no longer set by clicking on
Jupiter, then Display, then Options, then entering the GRS
longitude. That method had three disadvantages: it wasn't very
clear that this was what one was supposed to do, and it was easy
to have the default (now very elderly) value in there, and there
wasn't a good way to have it vary to follow the historical record
(the way the GRS drifts semi-randomly over time).

Now, the GRS longitude is determined using data in the file
grs_lon.txt. Documentation is provided at the end of that file.
Basically, it's just a list of observations of the GRS longitude
at various dates; Guide interpolates within those observations.
The GRS longitude is then listed in 'more info' when you click
on Jupiter."

Your e-mail caused me to realize that 'grs_lon.txt' needed a
bit of updating. According to the Sky & Telescope Web page for
the GRS, its longitude was 138 degrees in August 2009. I've
added that value to 'grs_lon.txt'; if you download

http://www.projectpluto.com/grs_lon.txt

(about a 6 KByte file) to your Guide folder (replacing a copy
that already exists there), and then run Guide, you'll suddenly
see the GRS where it ought to be. Thanks for nudging me on this.

-- Bill