The return of 15TH Century Comet: Comet Ikeya-Zhang

It’s summertime. The air is warm and the skies are clear. A perfect time to gather family members and friends and stay under the canopy of stars and watch the summer constellations and planets travel across the night sky.

And if you haven’t seen a comet, this is the best time for you to see one.

Comets, for superstitious folks, are nothing but omens of bad things to come. But for scientists, comets are pristine debris from the formation of the solar system 4.5 billion years ago.

They are composed primarily of icy and rocky materials. Comets may have struck the Earth in its infancy, seeding oceans with water. The study of comets gives astronomers the chance to know how the solar system was formed.

On Feb. 1, 2002, Kaoru Ikeya of Shizuoka prefecture, Japan, and Daqing Zhang in Henan province, China discovered a comet in the constellation Cetus, the Whale. Both described the comet as a small glow with no mention of a tail.

Since it is the privilege of discoverers to assign a name to the comet they discovered, the comet is officially called Comet Ikeya-Zhang.

Calculations made by astronomers indicate that the comet passed closest to the Sun last March 18 at a distance of 76 million kilometers. It will continue moving toward the Earth and will make its closest swing to the planet on April 28 at about 60 million kilometers.

Scientists estimated that the comet’s period of revolution is 400-500 years. If this is so, then Comet Ikeya-Zhang must be the same bright comet written in Oriental records in the year 1532.

The brightest comet since 1997’s Hale-Bopp, Comet Ikeya-Zhang will grace the dawn sky a week from now.

On April 13, at 4 o’clock in the morning, the comet may be seen at an altitude of seven degrees above the horizon and 37 degrees northeast. It is seven degrees to the right of the star Caph in the constellation Cassiopeia, the group of five bright stars that form a letter "W" pattern. The comet will move progressively north in the sky for the whole month of April (see star map).

The comet is as bright as the dimmest star the eyes can perceive. Although skywatchers may be able to see the comet in extremely dark and clear skies, observers are advised to use binoculars or small telescope to see the comet’s fuzzy head (or coma) and its tail.

(The author is a member of the Philippine Astronomical Society. He may be contacted at [email protected] or cellphone no. 0917-2706262.)