Science Update 01(Eclipses)

Feb. 20,2008: Total Eclipse of the Moon

Mark Wednesday, Feb. 20, on your calendar as "Lunar Eclipse Night," for if the weather is fair you should have no difficulty observing a total eclipse of the moon.

The eclipse will be visible wherever the moon is above the horizon during the time frame that the eclipse is taking place. As it turns out, North and South America will turned toward the moon and will be in excellent position for this sky show.

Europe, Africa and a part of western Asia will also be able to see the eclipse, although for these regions the event will take place in hours just before sunrise on the morning of Feb. 21.

All told, given clear skies, about three billion potential eclipse viewers will be able to partake in the spectacle of the full moon becoming completely immersed in the Earth's shadow.

This will be the third total lunar eclipse within the past year. The previous two favored different parts of North America, but this one will be readily visible from start-to-finish across much of the continent, weather permitting.

The total phase will last 51-minutes and begins at 10:01 p.m. EST (7:01 p.m. PST).

Because some of the sunlight striking the Earth is diffused and scattered by our atmosphere, the Earth's shadow is not completely dark. Typically there are coppery red and orange hues cast over the moon at and near totality from sunlight refracted from our atmosphere around the edge of the Earth, giving the moon the appearance of an eerie glowing ball.

As a bonus, during the eclipse the moon will be situated, in our sky, near the planet Saturn and the bright bluish star Regulus in the constellation of Leo. The effect will be to create a uniquely beautiful triangle in the sky consisting of the totally eclipsed moon, a bright naked-eye planet and one of the 21 brightest stars in the sky.

Note: SPACE.com will provide a complete eclipse viewer's guide Feb. 15.

Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for The New York Times and other publications, and he is also an on-camera meteorologist for News 12 Westchester, New York.

Souce:http://www.space.com/spacewatch/080207-lunar-eclipse.html

The Planets

Mercury

Mercury is often a difficult planet to find, but there are certain short periods each year when it can be seen with the naked eye with little effort, either just after sunset or before sunrise.

In 2008, Northern Hemisphere observers will find two periods when Mercury can easily be located. During the first half of May, Mercury can be seen low in the west-northwest soon after sunset. It is magnitude -0.7 on May 4 and has faded to +0.5 by greatest elongation on May 14 and fades rapidly after that. In late October, Mercury is well placed in the east-southeast before sunrise.

Southern Hemisphere observers will find Mercury well placed in the morning sky during early March and will rise well before twilight begins. In September, Mercury is well placed during the evening after sunset for southern observers.

Date	Event	Degrees from Sun	Magnitude	N. Hemisphere	S. Hemisphere	Visibility
January 22	Greatest Elongation East	19	-0.5	Fair	Poor	Evening
February 06	Inferior Conjunction
March 03	Greatest Elongation West	27	+0.1	Poor	Good	Morning
April 16	Superior Conjunction
May 14	Greatest Elongation East	22	+0.5	Good	Fair	Evening
June 07	Inferior Conjunction
July 01	Greatest Elongation West	22	+0.5	Fair	Poor	Morning
July 29	Superior Conjunction
September 11	Greatest Elongation East	27	+0.2	Poor	Good	Evening
October 06	Inferior Conjunction
October 22	Greatest Elongation West	18	-0.6	Good	Poor	Morning
November 25	Superior Conjunction

Venus

Venus is not well placed for observation most of the year. Superior conjunction, when it is on the far side of the Sun relative to the Earth, is on June 9. Venus will be best seen as a morning star in January and February, and as an evening star in November and December. The planet can be seen in the daytime sky with the naked eye if one knows where to look for it, especially around the times of greatest brilliancy and greatest elongation. Try following the planet before sunrise when it is in the morning sky and keep an eye on it until after sunrise.

Date	Event	Magnitude
June 09	Superior Conjunction	-3.9

Mars

Mars is just a week past opposition as the year begins, dominating the nighttime sky. It will be well placed for observation with a telescope until mid-February, when its diameter drops below 10 arcseconds. In July it becomes hidden in the SunÕs glare, not to re-emerge in the morning sky until early in 2009.

Date	Event	Magnitude
December 05	Conjunction	1.3

Jupiter

Jupiter spends the whole of 2008 in Sagittarius, making it poorly placed for northern observers. It will be high in the sky for southern hemisphere observers. It is best viewed in the morning sky from February until the July 9 opposition, when it moves into the evening sky. It becomes invisible late in the year near conjunction. The angular diameter at opposition will be 47.4 arcseconds. Binoculars will show the four largest satellites. A small telescope will show two of the cloud bands across the visible surface of the planet.

Date	Event	Magnitude
July 09	Opposition	-2.7

Saturn

Saturn will spend the entire year in Leo. Saturn can be viewed in the evening sky until August, when it approaches conjunction with the Sun. From October to the end of the year, it will be visible in the morning sky. The ring system will vary in tilt between 1 and 10 degrees this year. The maximum possible tilt is 27 degrees, which last occurred in 2003. The rings will appear edge-on in 2009. At opposition, the angular diameter will be 20.1 arcseconds. A small telescope will show the rings and one or more of SaturnÕs many moons.

Date	Event	Magnitude
February 24	Opposition	0.2
September 04	Conjunction	0.8

Uranus

Uranus is best viewed in late summer and early fall. It is in opposition on September 7, when it moves from the morning sky into the evening sky. Although it may be seen with the naked eye in a very dark sky, usually binoculars will be required to make it out. Its angular diameter is less than 4 arcseconds.

Date	Event	Magnitude
March 5	Conjunction	5.9
September 7	Opposition	5.7

Neptune

Neptune is best viewed during the summer and is in opposition on August 15 when it moves from the morning sky into the evening sky. Binoculars or a small telescope will be required to see it. The angular diameter is about 2 seconds of arc.

Date	Event	Magnitude
February 11	Conjunction	8.0
August 15	Opposition	7.8

Source:http://www.space.com/spacewatch/planets_2008.html