Shahin, if you really mean photos of stars or star trails, then you need long exposures. Maybe 25-100 seconds at f/4 on ASA400 film for stars. Maybe. Photos by starlight, away from the city, even longer exposures.
If you mean photos at night, in the city, that's different. Lights in the city should be bright enough to make pictures with a 2 sec exposure. Use a tripod and give it a try.
Look at Fred Parker's "Ultimate Exposure Computer" for some guidance. He has suggestions for all these conditions. http://www.fredparker.com/ultexp1.htm