Original Trippensee Planetarium (LSE) The Trippensee® planetarium (EL- 400) and the motorized Trippensee® planetarium (EL- 500) are orreries that perform the same functions; the difference being that the motorized model contains a spring wire connection to the red arm which moves the planetarium arm to revolve the Earth, moon, and Venus balls around the sun. These planetariums are durable and reliable gear and ladder chain driven so that the Earth maintains it’s 23-1/2° axis, revolves around the sun and rotates on it’s axis, all at the same time. The moon revolves around the Earth and keeps it’s one face toward the Earth. Venus also revolves around the sun, and can be positioned by hand, as well, to show phases and where it is located as the morning or evening star.   Among the phenomena which the models show are the following: Phases of the moon Eclipses of the sun and moon Causes of night and day Seasons in various parts of the Earth Reasons for winter and summer What the solstices and equinoxes are The axis of the Earth and its relationship to the North Star About the tides and their causes The Earth’s equator, latitude, longitude and meridians   The Trippensee models have been produced for over 90 years and provide many visual demonstrations that clarify the relationships of these elements of the solar system, in motion, for children and adults interested in learning more about the universe around them. The chain and gear drives on this model provide an exceptionally long life for the product and provide a model that is unequaled in the marketplace today. An instruction book, Elements of Astronomy and Physical Geography, is included.   Height: 14" Arm length: 16 1/2" Sun: 5 3/4" Earth: 3" Globe color: Light blue or black oceans (may vary from picture) EL-401 requires 12 volt DC power supply Qty :