Margie Scheibel, age 12, of Belleville, Illinois, for her question:

Which constellations are visible summer,and winter?

North of the equator, Polaris shines down on us every night of the year. In the skies above Saint Louis, you can locate it about 39 degrees above the northern horizon. This is because the city is located near Latitude 39 degrees,North of the equator. In case sky distances bewilder you, one degree of sky distance equals almost twice the width of the full moon. And Polaris is not alone Up There    summer and winter. In our latitudes, several starry constellations appear every night of the year.

The word "circumpolar" means around the pole. In celestial matters, the north pole is up in the sky above the earth's North Pole. And Polaris, the North Star, marks almost the exact spot. This realm of the night sky is not as densely populated as some. But a few constellations stand out with vivid stars. These are circumpolar constellations. Not only are they grouped around the celestial north pole, they also swing in orderly circles around the North Star. Most of these stars are seen up there in our skies  ¬summer and winter.

Polaris is in the center of a celestial circle about 160 times the width of the full moon. Five circumpolar constellations lie within this circle and every calendar day they swing around the central Pole Star. Polaris is the bright gem at the end of the Little Dipper's handle. It forms a straight line with the two pointer stars in the Big Dipper. The constellation Draco, the Dragon, sprawls its starry tail between the two Dippers and arches toward the far side of the circle.

Near where Draco bends back its snaky neck is the constellation Cepheus, the King. It is a square with a pointed roof and looks like a dog house made of five starry diamonds. Next to the King, almost opposite the Big Dipper is Cassiopeia, the Queen. The five brightest stars of this constellation look like a letter M or W, depending on which way up it is.

The radius of this faithful circle is 40 degrees. Its stars are all visible summer and winter at Quincy, Missouri, which is pretty close to Latitude 40 degrees North. Farther south, Draco's nose and the tip of the Big Dipper's handle sometimes dip below the horizon. Farther north, Polaris is fixed higher in the sky. At the North Pole it stays directly overhead and the turning of the earth makes all the circumpolar stars appear to circle around the roof of the sky.