`Mythical' Chelm Located on Map

In a review of the new musical ``Schlemiel the First'' (``New Music Based on Jewish Folk Characters,'' May 31), the author refers to ``the mythical town of Chelm, the place invented by Isaac Bashevis Singer for his children's stories.'' Though Singer may have used the town of Chelm as a setting for some of his stories, he did not invent the town, nor, in fact, is it mythical.

For generations, Jews have told stories and jokes about the amiable fools of Chelm, though no one is sure why this town came to be associated with nincompoops. In addition to the legendary home of fools and simpletons, there is actually a town in Poland called Chelm, located about 40 miles east of Lublin. Mark S. Alsher Philadelphia

Supernova lights up ancient history

The author of the article ``Hubble Telescope Finds Signs of Black Hole and of a Supernova's Strange Two Rings,'' May 26, is a little off the mark when he reports that the supernova 1987A exploded as a supernova seven years ago. It actually exploded 169,000 years ago - the distance in light years from our planet.

The light from the explosion arrived here seven years ago and was the agency for our learning of this long-ago event.

In the interim, that light traveled 186,000 miles/second x 169,000 years, a distance equaling approximately 1 x 1018 miles.

If there is a supernova out there exploding today, it is worth musing whether there will be intelligent life on Earth to detect its light when it arrives here many thousands of years hence. John Tanton Petoskey, Mich.