Hi there and a warm welcome to the forum. My wife and I love the Pyrenees, we have often holidayed in the western Pyrenees and we once climbed La Rhune, a great achievement for me. Haven't been there recently, but last year we took a trip to Saint-Jean-de-Luz, our favourite beach in the area, from a trip to northern Spain, so we have had some great times there.
On the subject of astrophotography, the first thing you need to do is get a copy of Steve Richard's 'Making Every Photon Count', it's the 'bible' of astrophotography, found here: https://www.firstlightoptics.com/books/making-every-photon-count-steve-richards.html
Good luck & clear skies!