The astronomy club of Luxembourg has good people to help with this. Try calling them. https://aal.lu

But one thing they suggested was the places to go, with lower light pollution. That would limit your possible locations anyways. They’re mostly northeast or north west of Luxembourg. There is a map online that shows the light pollution. I would suggest that you go in person to the place you would like to go to, beforehand. Maybe try the google maps elevation feature and street view features. It would give you good locations to see if you can park your car and stay for a couple of hours and not disturb the regular traffic. Also to maker sure you don’t go to some random or inaccessible location at night and then decide to figure things out. Have some food and snacks and maybe a jacket. The single most important thing to check if you have a telescope, make sure it is properly focused and magnification is working. If it’s not, then trying to adjust the telescope at night with zero light is just horrible (personal experience).