When you look up at the sky on a clear night away from all the lights from buildings what do you see?  Stars, the moon, maybe a or planet...  But what do we learn when we look up at the sky?  Sure, we can pick out a few constellations, notice that the stars change their postions in the sky throughout the year, or be entertained by a lunar eclipse.  But when we look up at the sky with only our eyes, we do not really understand the properties of the objects we observe.  So how do we learn about these intriging objects?  Back on Earth, we can look at an object, touch it, and make pretty good guesses of the components that make up the object.  But we do not have the luxury of seeing the objects in the sky up close.  Or do we?  How do scientists know so much about these objects?  You've guessed it!  Of course, they use telescopes. 

There are different kinds of telescopes.  Some examples include, optical telescopes, radio telescopes, and x-ray telescopes.  To learn more about telescopes click on the images below.

So why would an astronomer use an x-ray telescope to study the objects in the sky?  Click here to find out.