The planetarium is quite an impressive building to behold, particularly at night when it lights up. There's a cool museum if you're into this sort of thing and/or astronomy based shows which are held most days. On Friday evenings there are also sometimes special shows on with live music or a DJ.
The planetarium is worth a visit, even if it's just to admire it from the outside. The shows are however quite impressive so it's worth checking one out and you'll find all details of upcoming events/shows on the website.
Most of the shows are in Spanish
Mon-Sa: 14:00-19:00