Thanks to the folks who recommended Firefox as a solution to my problems
with CSC, and while I'm sure that it would be a great idea to switch from
IE, here's the answer to the *real problem* I was having with CSC (which I
now find to work):

Quote from the website:

"2008, Oct 17. I'm having server problems. It's causing many clear sky chart
images to not display.
I have two load-sharing servers. One of my two webhosters moved my site to a
new datacenter, breaking that copy of my site in the process. (Their
motivation was to improve reliablity. ahem. ) So half the time, CSC users
were looking at broken webpages.

I've switched the traffic over to the one working server, so CSCs should be
displaying again.'

However, it might take me a couple of days to fix the root cause of the
problem.

During that time, if you can't see a CSC image, try using the url
http://server2.cleardarksky.com (instead of http://cleardarksky.com). But
don't book mark it. I reserve the right to stop supporting server2.

Time to shop for a new webhoster."