It is indeed open to the public, I’m certainly no-one special:)
As far as I remember it was open from 10:00 – 14:00 then 18:00 to later? Please check first as I’d hate to ruin your visit.
It doesn’t seem that well advertised as our hotel knew nothing about it, kept trying to send us to the National Museum, full of old buildings and boring stuff like that;)
We went on a Thursday morning and were the only ones there, it being their weekend this seemed a bit surprising but we were told it gets busier in the evenings.
Hope you enjoy it,
John