I don't think you can mirror the site : the page uses javascript and is browser
dependent. 
If you use msie add to the url to mirror
<http://mondgesaenge.de/MGES/morromap/map.htm>
you may have to add
<http://home.arcor.de/schlauerhamster/map/index.htm>
If you use another browser, then the urls are
<http://mondgesaenge.de/MGES/morromap/ns_overview.htm?60,140>
<http://mondgesaenge.de/MGES/morromap/ns_map.htm>
<http://mondgesaenge.de/MGES/morromap/ns_title.htm>
<http://mondgesaenge.de/MGES/morromap/ns_tabs.htm>
<http://mondgesaenge.de/MGES/morromap/ns_locations.htm>

You can add all the urls and try, but you will have to find in the downloaded
pages the links to the pages called by the javascript routines. Hundreds of
links and a lot of work...