What is a telescope? How they work: Follow the light through a telescope using Ray Diagrams. What Instruments are used? What is image data? Where are the best places for telescopes? The problems with the Atmosphere. Satellite telescopes. A virtual tour of the Telescopes of the World. Information about Space Probes. A Glossary of terms.
National Schools'Observatory
Because of changes in the orbit's of the Earth and Moon, we find that the height of the tides differs on a daily basis.