Yes, is open everyday
Castle's always open, the museum has specific hours. We went on a day that the museum was not open and were able to wander around the grounds, just not see the museum.
Here is what was on their website: From 16 June to 30 September-Friday, Saturday and Sunday from 11:00 to 19:00 (ticket office closes at 18:30) Closed on Mondays
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