Compare and Contrast Lunar and Solar Eclipse





By looking at the geometry below, youíll see that a lunar eclipse occurs when the Earth is between the Sun and the Moon. The Earth blocks light from reaching the Moon. This results in lunar eclipse.


Lunar Eclipse Geometry

By looking at the geometry below, youíll see that a solar eclipse occurs when the Moon is between the Sun and the Earth. The moonís shadow casts on the Earth, hence resulting in solar eclipse.†††††

Solar Eclipse Geometry


Lunar eclipses can only occur during a full moon and when the moon is on the ecliptic plane. Only during full moon, the Sunís light will be blocked.

Solar eclipses can only occur during a new moon and when the moon is on the ecliptic plane. As this is the time when the moonís shadow casts on the Earth.

The total phase of a lunar eclipse can last for 90 minutes or more. The maximum time a lunar eclipse can last is 3 hours and 40 minutes.

The total phase of a solar eclipse may last only a few minutes. The maximum time for a total solar eclipse is 7 minutes and 40 seconds.

Lunar eclipses can occur up to 3 times a year. The number of lunar eclipses per calendar year can vary from two to five if penumbral lunar eclipses are counted. In a penumbral lunar eclipse, the Moon only passes through the lighter, penumbra or outer part of the Earth's shadow. Since penumbral eclipses are often inconspicuous, the number of conspicuous (i.e., umbral) lunar eclipses can range from zero to three each calendar year.

Solar eclipses can occur at least 2 and no more than 5 times a year.


Lunar eclipses are visible over an entire hemisphere (the side that is experiencing night time). This is because the moon is above your horizon at the time of the eclipse.


Solar eclipses are visible in a narrow path a maximum of 167 miles wide (269km.) as the Moon's shadow must pass over the location where the observer is.

Diagram: Eclipse Alignment

This diagram (wildly out of scale) shows a side view of the alignment. From anywhere in the grey penumbra, you will see some part of the sun shining from behind the moon. The penumbra is the area of partial eclipse. Only from within the tiny area where the dark umbra touches the earth will you see the sun completely covered and witness a total eclipse. Hence the possibility of seeing a solar eclipse at a specific location is rare which is also why solar eclipse-chasers often have to travel round the world to witness a solar eclipse.

At any geographical position, youíll be able to see a lunar eclipse when it occurs as long as you are on the hemisphere that is experiencing night time when the lunar eclipse occurs.

At any geographic position on the Earth, a total solar eclipse occur an average of once every 360 years. This is because for any geographical position, to see a total solar eclipse, not only does there need to be a new moon and that the moon is on the ecliptic, you also have to be in just the right spot on the earth. When you look up in the sky at the sun and the moon, you notice a strange coincidence--both look the same size in the sky. Both the sun and the moon look about one-half degree in diameter. Now, they're not really the same size. The sun's diameter is actually 400 times the moon's diameter. But, you must also take into account that the sun is also 400 times further away from the earth, reducing its apparent size to the same as the moon's. Because of this relationship, when you are standing on the earth, looking up at the two, you must be in a very limited zone to see the moon cover the entire face of the sun. If you were to move a little north, the sun would peek out over the top of the moon; a little south, and the sun shines past the southern limb of the moon. The match is so good that the "path of totality" is never more than 167 miles in diameter, and is usually less. This means that very few people have seen a total eclipse because the shadow only covers a very small area on the earth.


We can observe lunar eclipse with our naked eyes. To view a lunar eclipse, we do not need any equipment as it is not intensely bight. Therefore, it will not hurt our eyes.

Whether the solar eclipse is total, annular or partial, we still cannot observe it with our naked eyes. This is because the solar eclipse is intensely bright and cannot be viewed safely without eye protection.

A Solar eclipse always occurs two weeks before or after a lunar eclipse.As solar eclipse occurs in new moon and lunar eclipse occurs in full moon, the duration from a new moon to a full moon is usually about two weeks.