Man in the moon to make a pass at lovely Venus Heavenly rendezvous is tomorrow night

February 23, 1993|By Frank D. Roylance | Frank D. Roylance,Staff Writer

The appearance of a bright star beside the crescent moon makes a striking sight, one that at least five Islamic countries have worked into their national flags.

Tomorrow evening, if the weather cooperates, Marylanders will be able to see the same image beautifully displayed as a slender crescent moon and the brilliant planet Venus pass each other in the evening sky.

"Teamed up, they can attract notice even from the most nose-to-the-ground pedestrian," said Herman Heyn, Baltimore's street-corner astronomer.

The National Weather Service forecast was hopeful, calling for mostly clear skies tomorrow and Thursday. Temperatures should be around freezing by sunset.

The moon and Venus -- the second- and third-brightest objects in the sky -- last passed so close to each other on April 19, 1988.

"So eye-catching was it that even today, when I am in public with my telescope, I receive glowing comments on it," Mr. Heyn said.

The pairing of the moon and Venus in the evening sky -- known to astronomers as a conjunction -- will become visible shortly after the sun sets at 5:53 p.m.

Venus is at the point in its orbit when it shines the brightest as seen from Earth. It will appear as the bright evening "star" in the western sky. The moon will be three days past its dark, or "new" stage, and will appear as a slim crescent just below Venus.

"Through small telescopes or even firmly held binoculars, Venus itself shows a small crescent form," Mr. Heyn said.

The crescent shapes result from the positions of the moon and Venus relative to the viewer and the setting sun. If the sky is clear enough, observers also may be able to see the dark portion of the moon's disk faintly illumined. The phenomenon is called Earthshine. It is created when sunlight reflects from the clouds and oceans on the daylight side of Earth onto the moon, then back to the night side of Earth.

From the time the sun sets, until the moon sets about three hours later, the moon and Venus will appear to move closer and closer together. In reality, of course, Venus is about 40 million miles beyond the moon.

About 11 p.m. EST, the moon will actually pass in front of Venus, in what is called a "lunar occultation" -- a sort of eclipse of Venus by the moon. Unfortunately, it won't be visible from the United States.

The "star" and crescent is emblazoned on the flags of several Islamic countries, including Algeria, Mauritania, Pakistan, Turkey and Tunisia. Its origins are not entirely clear.

A spokesman at the Islamic Center in Washington said the crescent has been a symbol of Islam for centuries and is derived from the Muslim lunar calendar. The appearance of this crescent moon, for example, represents the start of the holy month of Ramadan. The added symbolism of the star is not uniform across the Islamic world, he said.

At the Algerian Embassy, a spokesman said the star and crescent on the nation's flag represent the ties between the state and the Islamic faith.

Photographers hoping to capture the celestial ballet on film will be able to see both objects within the field of a 500 mm lens.

"But the scene is best captured by a normal 50 mm view, which includes terrestrial scenery for perspective," Mr. Heyn said.

Shutterbugs should have a tripod to hold their cameras steady. Use 400-speed color film, and a one-second exposure at f/2.8.

"For insurance, bracket your shots a few f-stops each way," said Mr. Heyn, adding that the best time for taking pictures will be midway between sunset and twilight, about 6:40 p.m. "It is then that the sky presents its most pretty azure backdrop." If skies are clear, Mr. Heyn said he will set up his telescope at the rear door of the Rotunda shopping center in Baltimore, "Anyone who cares to is welcome to come have a look."

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