The answer to that question depends depends on what you want to shoot. Telephoto lenses are great for deep-sky object photography and can be combined with a star tracker to produce incredible images of galaxies and other celestial objects.
However, if you're looking to photograph the night sky while including a foreground landscape, you'll want to opt for a wide-angle zoom lens. Wide-angle zooms are easier to focus as the stars are so much smaller on their sensor.