Solar Eclipses

The solar eclipses occur during the New Moon, when the Earth enters the umbra or penumbra of the Moon. When the Earth only crosses the penumbra of the Moon we have a partial eclipse of the Sun. When the Earth crosses the axis of the Moon’s umbra we have central solar eclipse. There are two types of central eclipses: the total eclipses, when the apparent diameter of the Moon is bigger than that of the Sun (the Sun is fully eclipsed), and the annular eclipses when the apparent diameter of the Moon is smaller than that of the Sun. There is a special case where the apparent diameter of the Moon is smaller than that of the Sun at the beginning of the eclipse, then bigger (around the maximum) and then smaller again, the eclipse is then called a total-annular eclipse or hybrid eclipse as the one on April 8, 2005.
Those who were lucky enough to witness a total solar eclipse, in an unusual surroundings with a nice weather, can testify of the outstanding beauty of such an event. An eclipse of the Sun occurs on average every 18 months (often in hardly reachable locations), but the eclipse is only visible from a small band - the Path of Totality - and with an average duration of three minutes (maximum duration just over seven minutes). This is why observing such an event must be well planned in advance as shown in those various scouting trips. You don’t want to find yourself in such inconvenient situation. Choosing your viewing location according to the phenomena you want to observe is equally important. Those who want to concentrate on observing the event visually can rely on Solar Eclipse Maestro to automatically take pictures for them.

You can use this solar eclipse calculator to compute the local circumstances of an eclipse, and the solar eclipse timer notifies the beginning of the various events. A time exposure calculator is there to help you choose your camera settings. You can also subscribe to a mailing list to stay posted.
The interactive Google maps or the Google Earth kmz files let you explore the path of totality and compute local circumstances of contemporary eclipses. Or explore the Five Millennium (-1999 to +3000) Canon of Solar Eclipses and its 11,898 eclipses to help you prepare your eclipse journeys or study historical events.

Software: Solar Eclipse Maestro

This application controls up to 4 USB or Firewire connected cameras during a solar eclipse, so that you can be free to concentrate on observing the event visually. This brief overview will let you know more. Now available for download Requires: MacOS X 10.4.x (Tiger), 10.5.x (Leopard) or 10.6.x (Snow Leopard)

Dashboard Widget: Solar Eclipse Calculator

This widget is used to compute the local circumstances of a solar eclipse from 1970 to 2099. It is localized in English, French and Chinese. This brief overview will let you know more and download it. Requires: MacOS X 10.4.x (Tiger) or 10.5.x (Leopard)

Choosing your viewing site

Outside of meteorological constraints, you may also like to observe particular phenomena occurring during an eclipse.

For example choosing a location close to a farm, will enable you to witness the eclipse effects on the animal life. Don’t forget to look also at the plants.

The main choice you have to make is to choose between a location near/on the centerline or close to the edges of the path.
Consider the most colorful part of the Sun’s atmosphere: the innermost part above the Sun’s visible disc, the chromosphere. On the eclipse center line, the chromosphere is visible only for a few seconds between the disappearance of the Sun’s visible disc and the moment when the chromosphere itself disappears behind the Moon. Only during those precious few seconds, you can get a flash spectrum. However, watching from near the edges of the path, the disc of the Moon slides by the disc of the Sun for a prolonged period and the chromosphere can remain visible for 90 seconds or more. Because of the chromosphere’s rich redness, eclipse photos taken from near the path edges have more color in them than do photos from the center line. It is not just the chromosphere view that is prolonged near the path edges. The mysterious and elusive "shadow bands" are far more likely to be seen from sites near the edges, and they usually last two to five times longer than on the center line. The diamond rings and Baily’s beads will usually last up to 10 times longer. Moreover, while just a few beads may form and stay in place for centerline viewers, edge viewers can see numerous beads form and dissolve constantly; they seem to travel along the limb as the two discs glide past one another. Finally, prominences can be seen for longer.
For most total solar eclipses, as one moves off the center line by as much as 20 percent of the distance to the edge, the average duration of totality drops merely 2 percent. The true duration of totality is governed by irregularities (mountains, craters, valleys) at the Moon’s limb, so the longest eclipse may occur almost anywhere within this central 20-percent zone. Precise positioning on the center line has no real value.
The best overall views of the eclipse and related phenomena are generally seen at 95 percent of the way to the edge of the path, where the duration of totality is one-third of the centerline duration.

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