Hi Don,

Aha! Problem is that 15' on a side is the maximum
size available from the server. If your field of view
is larger than that, you'll still get an image centered
on wherever Guide is pointed, but it'll be just 15' on
a side.

And it looks as if the above paragraph is a little out
of date. Guide gets these images via the server at

http://archive.stsci.edu/cgi-bin/dss_form

You'll see that it looks as if the limit has been bumped
up to 60 arcminutes. To get Guide to recognize the changed
limit, hit Alt-J; you'll be prompted to "Enter test flag".
Enter this text:

MAX_DSS_DOWNLOAD=60

...and Guide will start grabbing chunks up to a full degree
across. Some patience may be needed; it should take sixteen
times longer than those 15' squares did.

-- Bill