WHERE: EXPLORIT at Mace Ranch Park, 3141 5th Street, Davis.

WHERE: EXPLORIT at 2801 Second Street, Davis.

Transit of Mercury!

Saturday, November 4, 2006
from 7:00 ˆ 9:00 p.m. at Explorit (5th St.)
Also:
Wednesday, November 8, 2006
from 2:00 ˆ 4:00 p.m. at Explorit (2nd St.)

Hosts: Vinita & Calvin Domier (530) 756-0191, vcdomier@yahoo.com

Join us Saturday, Nov. 4th, at 7:00 p.m., at Explorit‚s 5th Street site, when we will discuss Mercury, the planet closest to the Sun. We will highlight the upcoming rare planetary event, the transit of Mercury occurring on Wednesday November 8, 2006. We will also look at the night sky.

Also join us for a free viewing of the actual event on Wednesday, Nov. 8th, from 2-4pm at Explorit‚s 2nd Street site. Solar telescopes will be set up to view the 2006 transit of Mercury, weather permitting. A transit happens when a small body like Mercury or Venus moves across the face of a larger body like the Sun. The Mercury transit will begin at 11:12am and end at 4:09pm. Remember not to look at the Sun directly without proper filters!

Mercury is the smallest and innermost planet of the solar system. It is named after the Roman messenger of gods because it is also the swiftest planet, revolving around the Sun in just 88 days. It is hard to observe as it rises and sets close to the Sun. It can be glimpsed for a very brief period just before sunrise or just after sunset. At other times, it is lost in the Sun‚s blinding glare.

Mercury exhibits phases like the Moon and Venus, as it is an inferior planet with its orbit within Earth‚s orbit. At just before or just after superior conjunction (when the Sun is between Earth and Mercury), Mercury appears round like a full Moon. When it is at inferior conjunction (when Mercury is between Earth and the Sun), it is lost in the sun‚s glare like a new Moon.

Before and after inferior conjunction, binoculars and telescopes reveal bright Mercury‚s crescent phases. Mercury is at its brightest then, even though only part of it is illuminated, as its angular size is much bigger than that of its full phase size. This is because the planet is relatively closer to Earth at inferior conjunction than it is at superior conjunction.

During a rare inferior conjunction, when the orbit of Mercury is tilted just right, Mercury passes in front of the Sun‚s disk. The transit of Mercury across the Sun‚s face can be observed with a telescope (equipped with a proper sun filter) as a small black dot moving across the Sun from celestial east to west. Transits are miniature solar eclipses caused by a very narrow shadow cone of a planet, which obscures only a very tiny portion of the Sun.

A transit does not occur at every inferior conjunction due to the large 7° inclination of Mercury‚s orbit to Earth‚s orbit. This results in the planet crossing above or below the Sun from Earth‚s point of view. Mercury transits are possible only in May or November when its orbit crosses the plane of the ecliptic. Nov. transits occur in intervals of 7, 13, or 33 years and May transits occur in the intervals of 13 or 33 years. The next transit will be in May 2016.

Very little is known about Mercury as it very difficult to observe. NASA‚s Mariner 10 spacecraft performed 3 fly-bys in 1974-75 and photographed only 46% of the planet. They revealed a heavily cratered surface like our Moon‚s. NASA launched Messenger in 2004 to unlock the secrets of Mercury when it orbits the planet in 2011.

Sky Info for November 2006

Leonids Meteor Shower peaks on the night of Nov. 18 - 19. This meteor shower results from the debris left behind by Comet Tempel-Tuttle. The meteors will appear to radiate out in all directions from Leo.

Planets: Jupiter (mag. ˆ1.6 in Libra) is a very bright planet low in the southwestern evening sky, setting ~ 6pm. Venus (mag. ˆ3.8 in Leo) and Mars (mag. +1.6 in Leo) are setting ~ 5pm in the western sky. Saturn (mag. +0.5 in Leo) is a bright planet in the eastern sky after midnight, rising ~ 12am.

Moon phases: Full: 11/5, Last Qrt.: 11/12, New: 11/20, First Qrt.: 11/27.

*Free download of monthly sky maps and calendars available at www.skymaps.com .

To Receive These Bulletins via E-mail Contact Explorit at: Explorit Science Center

The Astronomy Club is for everyone - adults, children, knowledgeable or ignorant. Come to listen, look and learn, or to share your expertise or experience.