Lunar Eclipse
28 August 2007
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Common Name: Lunar Eclipse Other Names: RA: Dec Constellation: Capricorn Distance: 1 light second Magnitude: Telescope: Orion ED80 Camera: Canon 300D Filters: nil Exposure: Date: 28/8/2007 Where: Skywatch Observatory, Coonabarabran Lat: 31 16 35.05 S, Long 149 11 33.99 E, Elevation 547metres Notes: Coonabarabran was treated to a spectacular Lunar Eclipse. The eclipse started at 5:55pm when the Moon moved into the outer shadow cast by the Earth from the Sun (penumbra). The eclipse was more noticeable when the Moon moved through the inner darker shadow called the Umbra at 6:55pm when the Moon became noticeably dimmer and started to take on a deep coppery red colour. It appeared a big bite was taken out of the Moon by 7:15pm. This clearly demonstrated that the Earth’s shadow is round and is proof that the Earth must be a Sphere and not flat. The Babylonians worked this out from lunar eclipses thousands of years ago. By 7:50 pm the Moon was totally eclipsed and the sky was significantly darker with the Milky Way clearly visible casting its own shadows of “The Emu” (an aboriginal constellation only seen on moonless winter nights) across the sky. This was viewed by amazed onlookers at Skywatch Observatory. Totality concluded at 9:25pm when the moon slowly appeared out of the Earth’s shadow and the show concluded at 11:20 pm. A lunar eclipse occurs when the Sun, the Earth and the Moon line up and can only occur when the Moon is full. The moon is not completely blackened but is a dark red colour. The Earth’s atmosphere refracts the Sun’s light and a small amount of light reaches the Moon. The blue light is scattered leaving the red light to filter through to the moon. This red colour can vary from eclipse to eclipse depending on the amount of dust and clouds in the Earth’s atmosphere. A lunar eclipse does not occur every Full Moon, as the orbit of the Moon is inclined 5.1 degrees above and below the Ecliptic. So most of the time the full moon is either above or below the Earth’s shadow. The Full Moon will cross the ecliptic twice a year so there can be a lunar eclipse somewhere on the Earth twice each year. The timing varies due to a wobble in the Moons orbital inclination and its precession around the Earth every 18.5 years. The ecliptic is the path the sun traces across the sky. This named is derived from eclipses which can only happen when the full moon crosses the ecliptic. There are two types of shadow, the Penumbra or outer shadow and the Umbra or the inner shadow. The next total lunar eclipse for Coonabarabran is on the evening of December 21, 2010, though we will be teased in August 17, 2008 by a partial lunar eclipse in the minutes before sunrise.