Astronomical Observations Eclipses

Information About Eclipses Definition Schedule Terms Reasons

Moon Orbit and Rotation

Lunar Month vs. Sidereal Orbit

Definition of an Eclipse Solar Eclipse – the moon interrupts light from the sun Lunar Eclipse – the earth interrupts light shining on the moon

Size of the Shadows Solar Eclipse – Sun 400x Larger than Moon, but is also 400x Farther away – Moon and Sun seem similar size when aligned, so the Moon can obscure the sun Lunar Eclipse – Earth’s shadow blocks sunlight on the Moon

Terms Umbra and Penumbra Total and Partial Annular Node

Terms

Frequency Lunar Eclipses – occur every 6 months, and total lunar eclipses normally come in sets of three, followed by three partial eclipses. The total eclipse can last from a few minutes to several hours. Solar Eclipses – can occur two to five times a year, but the majority are partial eclipses. – Total eclipses occur about once every 18 months, and affect a very limited area. The maximum coverage of the solar disk lasts between 6 and 7.5 minutes.

Schedule In 2014 there are two solar and two lunar eclipses: In 2014 – 2014 Apr 15: Total Lunar Eclipse – 2014 Apr 29: Annular Solar Eclipse – 2014 Oct 08: Total Lunar Eclipse – 2014 Oct 23: Partial Solar Eclipse Eclipses can only occur during a “Full Moon” (lunar) or a “New Moon” (solar) Why do you think there aren’t 12 solar and 12 lunar eclipses per year?

The Moon’s orbit is not always on the Ecliptic Plane

Annular Eclipses: The Moon’s orbit is not perfectly circular

NASA Eclipse Website

A Final Tidbit: Why a Total Lunar Eclipse is Red

Summary – 3 types of Solar eclipses

Summary – 3 types of lunar eclipses

Quiz Definition – Lunar / Solar Schedule – How Often Terms – Umbra, Penumbra, Total, Partial, Annular, Node Reason for frequency – planes of orbit (nodes) Reason for Annular – aphelion vs. perihelion Question – Why do more people see lunar eclipses than solar eclipses?