A pair of binoculars is a great way to get started in astronomy, birding, and just as an addition to your hiking kit.
For Astronomy, choose binoculars that have a lower magnification so you can more easily keep your view steady. Binoculars with a 40mm - 60mm aperture are good for hand-held use. Anything larger and heavier will really require a tripod to hold steady.
Also look for waterproof and fog proof lenses. You'll pay a bit more for these models, but it will be well worth the investment on a humid night!