It's no illusion. Some full Moons are genuinely larger than others and this Friday's is a whopper. Why? The Moon's orbit is an ellipse with one side 50,000 km closer to Earth than the other.


Courtesy of NASA

In the language of astronomy, the two extremes are called "apogee" (far away) and "perigee" (nearby). On December 12th, the Moon becomes full a scant 4 hours after reaching perigee, making it 14% bigger and 30% brighter than lesser full Moons we've seen earlier in 2008.


Courtesy of NASA

Above: In 2004, Greek amateur astronomer Anthony Ayiomamitis photographed an apogee Moon and a perigee Moon, and set the images side by side to show the difference.

Here some fact about our Moon:

“The Moon is the only natural satellite of Earth. It's official name is Luna (latin for moon) to distinguish it from the generic "moon", however it often, day by day, goes by the name Moon, as this was what it has been traditionally called. Apart from the word lunar, the terms selene/seleno and cynthion (from the Lunar deities Selene and Cynthia) refer also to the Moon (aposelene, selenocentric, pericynthion, etc.). The average distance from the Moon to the Earth is 384,403 kilometers (238,857 miles). The Moon's diameter is 3,476 kilometers (2,160 miles).

Between 1969 and 1972, the U.S. Apollo program sent twelve men to land on the Moon, the first of which were Neil Armstrong and Buzz Aldrin in Apollo 11. The first men sent to the Moon were Frank Borman, James Lovell and William Anders, in Apollo 8. Before and since that time, the Moon has been the target of numerous landing and orbiting space probes, starting with the Soviet Luna 1 in 1959.

However, the most important fact about the Moon is that it is the only other body in the universe upon which human beings have walked. This is indeed a singular distinction.

The Moon is believed to have formed approximately 4.7 billion years ago when an object the size of Mars collided with the primordial Earth. The force of this collision released an enormous amount of debris into space, some of which settled into orbit around the Earth until it accreted into the Moon.

For centuries, the Moon has been a favourite target for astronomers. Obviously, it is the nearest and largest object in the night sky. When using a small telescope or binoculars, the best details can be found near the lunar terminator - the line separating night from day on the Moon's surface. A large instrument should be fitted with a lunar filter because even the weak light of the Moon can cause eye damage if viewed for extended periods through a large light-gathering telescope. There are three lunar features that are easy to spot with the naked eye, a pair of binoculars or a small telescope.

Marinas
These lunar "seas" (as they were called by the ancient astronomers) are the dark patches visible on the Moon's surface. Visible in the exact center of the first quarter moon is the most famous of all lunar seas, Mare Tranquilitatis, the 'Sea of Tranquillity', which was the site of the first manned Apollo landing. Other watery terms used to describe lunar features include: Oceanus (Ocean); Lacus (Lake); Sinus (Bay); and Palus (Swamp).

Craters
Named mostly after scientists, these objects are the result of meteoroid impacts. They can range in size from microscopic to more than 150 miles in diameter. Many craters have central peaks and ray systems extending away from the crater. The Copernicus and Kepler craters display excellent ray systems across the maria of the last quarter moon. Also visible at last quarter, the Tyco crater's ray system extends across much of the lunar surface. It is interesting to note that well into this century many astronomers believed that lunar craters were extinct volcanoes.

Highlands
The light-coloured bits of the lunar surface, this is the oldest and most heavily cratered surface on the Moon. The mountains of the Moon are usually named after mountain ranges here on Earth. A small telescope can often reveal long shadows extending from these mountainous regions.”

Really appreciate the effort of Astro Loh for organizing this outing and for the astrology knowledge he shared with us! Not to forget, the precious equipment that he allowed us to play around with. Oh ya one last thing, here’s some interesting information that he shared with us- the “volcano-like holes” which is the most visible is called ‘Tyco’, the largest crater on moon surface.

Outing member: Astro Loh, Kelly, Earn Min, Wing Yew & Me.

12th December 2008