The best spot would be one that is in total darkness, other than for light from the stars. Even your backyard would be perfect provided you base yourself in a spot that's away from city lights. Surrounding artificial lights tends to spoil the exposure and dim the effect the light of the stars create. Of course if you really want to get exotic there are fabulous locations across the world such as the fabled Green Mountain of Oman. There the Saiq Plateau home to Anantara Al Jabal Al Akhdar Resort at an elevation on 2,000 meters offers nothing but gorgeous rugged surroundings and wide expansive sky as your canvas. Here's a tip for those 'travelling astro-photographers' of all the Oman luxury resorts the one on the fabled green mountain is the Middle East's highest elevated five star resort; hence comfort and location for astrophotography does not get any better than this.