11.   Unlike optical telescopes, radio telescopes use no lenses.

12.   In fact, these starburst galaxies may be as common as all of the space objects spotted by optical telescopes.

13.   It will be several months before the object moves into the night sky and becomes visible to optical telescopes.

14.   Optical telescopes eventually will be used to measure the mass of the X-ray object.

15.   The observatory will use an array of optical infrared telescopes to produce extremely detailed images of the far reached of the universe.

16.   They cannot be seen by optical telescopes because they are camouflaged by dust that is characteristic of galaxies in their early stages of development.

17.   Unlike optical telescopes such as the orbiting Hubble, Arecibo listens to the sounds of space.

18.   Using these signals, scientists can create computer pictures of distant galaxies and interstellar gas clouds that are invisible to optical telescopes.

19.   It also helped gather evidence to support the Big Bang theory and provided the first convincing proof by an optical telescope of the existence of black holes.