The archives are held at www.irishnewsarchive.com which offers a variety of subscriptions to view historical papers from across the country. It's well worth a look.
I was lead to believe that the Southern Star archive collection was viewable, free, via the host site, but this didn't turn out to be the case. The only free route I found was direct from the newspaper's header. This may have been caused by a temporary problem. I've contacted the Irish Newspaper Archives; if there's any update on this, I'll make a note here.