1. Tools that help us see Celestial Objects Gr. 9 science exploration unit

2. A telescope is an instrument that allows us to see objects that are very far away. Telescopes use mirrors and lenses to collect beams of light from a source and produce a magnified image. A telescope can collect up to 1 million times more light than the human eye.

3. Types of Telescopes: 1. A refracting telescope uses lenses to magnify images. 2. A reflecting telescope uses a series of mirrors.

4. Telescopes are often placed high in mountains or in space to get a clearer view of the sky. Telescope operators work in observatories and control the telescopes using computers.

5. The telescope's magnification, its ability to enlarge an image, depends on the combination of lenses used. The eyepiece performs the magnification. Since any magnification can be achieved by almost any telescope by using different eyepieces, aperture is a more important feature than magnification

6. © 2004 Pearson Education Inc., publishing as Addison-Wesley Angular Resolution The ability to separate two objects. The angle between two objects decreases as your distance to them increases. The smallest angle at which you can distinguish two objects is your angular resolution.

7. Telescope Types Refractor – focuses light using lenses Reflector – focuses light using mirrors – used exclusively in professional astronomy today

8. Not everything is visible… Many modern day telescopes do not use visible light to collect images. Radio telescopes, x-ray telescopes and infrared (IR) telescopes have become a staple of modern day astronomy, producing some amazing images. www.yorku.ca/eye/spectrum.gif

9. Famous Telescopes Keck Telescope http://www.jpl.nasa.gov/events/lectures/dec04.cfm Kitt Peak Observatory http://www.jpl.nasa.gov/events/lectures/dec04.cfm

10. Very Large Array (VLA) radio telescopes

11. Light Pollution is excess light produced by cities and towns at night. This makes astronomical observations more difficult because the excess light overpowers the dim light coming from celestial objects.