Newsserver under gnus

[Fabian Braennstroem]

Hello,

right now I am making the first steps with gnus and now I have a first
question.
I set the newsserver with '(setq gnus-select-method '(nntp
"newssvr20-ext.news.prodigy.com"))' which works fine. But somehow I get
different newsgroups than I have with the same newsserver under opera;
e.g. comp.soft-sys.matlab and sci.physics.computational.fluid-dynamics
are missing with gnus, but exist with opera. 
Is there any explanation for that? What do I do wrong?

Thanks!
Greetings
Fabian