STAFF PICK: This 16-inch scope is the only free telescope open to the public in the state of Arizona. Open Wednesday through Saturday nights, 7-10 p.m., the telescope is staffed by volunteer operators who are well trained and passionate about watching the sky. On any given night visitors can get a good look at planets, nebulae, double stars, star clusters, the moon and maybe a galaxy. The volunteer operators explain everything you see, but even without interpretation the sight of a galaxy millions of light years away is just plain breathtaking. You can also get a good close-up look at how a big telescope works.