Total Solar Eclipse

135. Total Solar Eclipse


Position not available. Multiple objects or no NGC/IC designation
 

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A solar eclipse occurs when a portion of the Earth is engulfed in a shadow cast by the Moon which fully or partially blocks sunlight. This occurs when the Sun, Moon and Earth are aligned. Such alignment coincides with a new moon (syzygy) indicating the Moon is closest to the ecliptic plane. In a total eclipse, the disk of the Sun is fully obscured by the Moon. In partial and annular eclipses, only part of the Sun is obscured.

If the Moon were in a perfectly circular orbit, a little closer to the Earth, and in the same orbital plane, there would be total solar eclipses every new moon. However, since the Moon's orbit is tilted at more than 5 degrees to the Earth's orbit around the Sun, its shadow usually misses Earth. A solar eclipse can only occur when the Moon is close enough to the ecliptic plane during a new moon. Special conditions must occur for the two events to coincide because the Moon's orbit crosses the ecliptic at its orbital nodes twice every draconic month (27.212220 days) while a new moon occurs one every synodic month (29.530587981 days). Solar (and lunar) eclipses therefore happen only during eclipse seasons resulting in at least two, and up to five, solar eclipses each year; no more than two of which can be total eclipses.Total eclipses are rare because the timing of the new moon within the eclipse season needs to be more exact for an alignment between the observer (on Earth) and the centers of the Sun and Moon. In addition, the elliptical orbit of the Moon often takes it far enough away from Earth that its apparent size is not large enough to block the Sun entirely. Total solar eclipses are rare at any particular location because totality exists only along a narrow path on the Earth's surface traced by the Moon's full shadow or umbra.

An eclipse is a natural phenomenon. However, in some ancient and modern cultures, solar eclipses were attributed to supernatural causes or regarded as bad omens. A total solar eclipse can be frightening to people who are unaware of its astronomical explanation, as the Sun seems to disappear during the day and the sky darkens in a matter of minutes.

Since looking directly at the Sun can lead to permanent eye damage or blindness, special eye protection or indirect viewing techniques are used when viewing a solar eclipse. It is safe to view only the total phase of a total solar eclipse with the unaided eye and without protection. This practice must be undertaken carefully, though the extreme fading of the solar brightness by a factor of over 100 times in the last minute before totality makes it obvious when totality has begun and it is for that extreme variation and the view of the solar corona that leads people to travel to the zone of totality (the partial phases span over two hours while the total phase can only last a maximum of 7.5 minutes for any one location and is usually less). People referred to as eclipse chasers or umbraphiles will travel even to remote locations to observe or witness predicted central solar eclipses.



 
Supplementary Image




Supplementary Data or Comments

No idea what causes the artifacts in the 'diamond ring' image but it looks good. A comment on the journey. The trip down was great, the trip back not so much. It seems everyone decided to leave at the same time to head home. The 7 hour trip down took 11 hours going back. Much thanks to the folks at the farm in French Village for their hospitality and the wonderful meal.


Main Image Information

Location French Village MO
Date Aug 21 2017
Optics Astrotech AT65EDQ
Filters None
Mount Celestron CGE
Camera Nikon D810A
ISO 200
Subexposures 3
Exposure Length 1/400 1/6 1/3
Guider None
 

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