Tom Dahlke, age 11, of Olmsted Falls, Ohio, for his question: 

Is Vega a star of the first magnitude?

Magnitude is a measure of star brightness, and you would expect the brightest stars to be classed as first magnitude. But the classification is not so sensibly simple. If the brightest stars were first magnitude, then starry eyed Vega would have, to be listed as brighter than bright.

Vega is one of the four or five brightest faraway stars ever seen from our home in the heavens. The brightest of them all is Sirius, the Dog Star, which sparkles like a sapphire. on wintry nights north of the equator. On the scale of apparent brightness it is rated as minus yes, minus 1.4. In the summer skies of the Northern Hemisphere, the brightest star is Vega, the glittering white jewel of Lyra, the Lyre constellation. Astronomers list its visible magnitude as 0.04. If you think these figures are bewildering, then you agree with many expert and even more amateur astronomers.

Our system of rating stellar magnitude dates back to antiquity. A simple scale of six degrees of brightness was devised about 2,000 years ago. Since then, new skills and reams of data have been gathered with telescopes and other astronomical inventions. New classes have been added at both ends of the old scale and the original groups have been refined with decimal divisions. At best, the brightness comparison is built on a man made decision and the gradual addition of refinements has made it more and more cumbersome.

For example, the counting in the system is done backwards. A star of the sixth magnitude is 100 times dimmer than one of the first magnitude. You might expect it to.be six times dimmer, but the system says 100. This figuring is based on the reasonable idea that only a portion of a distant light reaches our eyes. Someone figured this ratio and it was adopted into the magnitude scale. The ratio in this conundrum is a little more than 2 1/2. So 2 1/2 is the difference factor between each whole degree on the scale.

A star of first magnitude is 2 1/2 times brighter than one of second magnitude. A third magnitude star is 2 1/2 times brighter than one of the fourth magnitude. Some celestial luminaries are brighter than first magnitude and the scale continues to count backward, even for them. A star of magnitude zero is 2 1/2 times brighter than one of first magnitude.

The brightest stars have minus numbers and, as in other groups, each whole number is subdivided into decimals. Sirius is minus 1.4. The sun is minus 27. The 0.04 of Vega means that ft is almost 2 I/2 times brighter than a first magnitude star. With a few more decimals, it would be in class 0 magnitude. This scale compares the brightness as ft appears to our eyes. Complicated astronomical skills are used to calculate the true magnitude of stars, taking into account the fact that the light is coming to us from different distances.

But the same cumbersome number system also is used to compare these zeal, ox absolute magnitudes.

We can admire the diamond glitter of Vega on a June evening. Find the head of Draco, the Dragon that winds its snaky body between the Dippers. Move eastward for a distance equal to the width of 30 full moons, and there is the brightest star of the summer skies. It forms a brilliant triangle with Deneb, about 60 full moons to the northeast, and Altair, about 80 full moons toward the east. Altair is rated almost exactly a first magnitude star and you can compare it with the extra brilliance of Vega.