With this simple technique, it is possible to capture constellation patterns, the Milky Way, and even bright nebulas such as the Eta Carinae Nebula and the Great Nebula in Orion. Only the brightest stars will record in light-polluted skies, so the darker the sky, the better.
Of course, the sky is always moving. How long an exposure you can use before the stars start to streak depends on the lens's focal length and on where in the sky it is pointed. Stars near the celestial equator, such as those in Orion, will trail more quickly than stars near the celestial pole, such as those in the Big Dipper.