NASA puts the number of orbital debris larger than 10 cm at more than 21,000 items, as of March 2012. NASA and other agencies monitor that debris because of the inherent danger to spacecraft, but their work is also helpful to any aspiring satellite hunter. There are resources to show you where to look overhead as well as maps that can offer information about everything above you. Here are some useful options:
Line of Sight: Created by artist and engineer Patricio Gonzalez Vivo, Line of Sight is a searchable map that shows the positions and the orbits of thousands of satellites. You can plug in your city and find out what is overhead in real time. When you click on an orbital path, the site lists information about the object, including whether or not it’s visible to the naked eye.
Satellite FlyBys: This site, created by SpaceWeather, tells you where certain objects are and when to view them. While it’s not a comprehensive list of all of the satellites, it does tell you where to look for some of the most famous objects in space like the Hubble, the International Space Station and a few spy satellites.treehugger 6 Tools to Help You Spot a Satellite