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Glossary

With Local Prediction of the Solar Eclipse, you can find local predictions of the phenomena.

Solar Eclipse

Mechanism

Solar Eclipse occurs when the Sun and the Moon gets nearly on the straight line and the Moon passes across the disk of the Sun. Since the orbit of the Moon tilts (about 5.1 deg.) against the orbit of the Sun, solar eclipse does not happen on every new moon when the Sun and the Moon are in the same direction (Figure). Solar Eclipse occurs at New Moon near the nodes. Caution! When you observe the solar eclipse, you MUST NOT directly look at the sun. Otherwise, you might loose your eyesight.

Types

Inside the penumbral shadow cone, you can see Partial Eclipse, and inside the umbral shadow cone, you can see central eclipse. When the Moon is near, the whole disk of Sun is covered by Moon (Total Eclipse). and when the Moon is far, the disk of Sun is not fully covered and looks like a ring (Annular Eclipse). Sometimes the location inside the Earth can be a factor for the phenomena (Annular Total Eclipse).

During total eclipse, we can observe mysterious scene. 1) It gets dark, 2) planet and bright stars appears in the sky, 3) Diamond Ring, 4) beautiful corona.

With Local Prediction of the Solar Eclipse, you can find predictions of eclipses.
Topics (Japanese Only)

• Major phenomena in 2012
• Total Eclipse on 2009/7/22
• Annular Eclipse on 1987/9/23
• Solar & Lunar Eclipse

Various Types of Solar Eclipses

Partial	Total	Annular

Eclipse Maps, Path of Central Phase

Not everyone can see solar eclipse. Eclipse Map shows the area where the eclipse is visible in red lines. You can say that it is the passage of Moon's Shadow. Because the Earth is round, there are several patterns in eclipse maps.

Inside the Central Phase, you can see central eclipse. The mark "*" shows the position of the center of the shadow of Moon. Outside of Central Phase, you can only see partial eclipse.

At left and right side of the Map are the sunrise or sunset lines. Inside the lines, the Sun rises or sets during eclipse (Figure).

Glossary

• Position Angles (P.A.)
  • p : Direction of the center of Moon with respect to the center of Sun, measured counterclockwise from celestial north
  • q : Direction of zenith with respect to the center of Sun, measured counterclockwise from celestial north
  • V : Direction of the center of Moon with respect to the center of Sun, measured counterclockwise from zenith, i.e. V = p - q.
• Other terms
  • S.D. : Semi Diameter
  • Dist. (d) : Angular distance between the centers of Sun and Moon.
  • Mag. (D) : Magnitude = Percentage of diameter of Sun covered by Moon. D = (Semi Diameter of Sun + Semi diameter of Moon - d) / (Diameter of Sun)
  • Obsc. : Obscuration = Percentage of surface area of Sun covered by Moon.