Star Points for September, 1998; by Curtis Roelle Fall Causes Dipper to Dip Ask a kid "when does summer end" and they might tell you on the first day of school. An adult may say summer ends when the swimming pool closes for the season or after the last "in-season" weekend at the beach, i.e. Labor Day. Officially in the northern hemisphere however, summer ends with the Autumnal Equinox which this year occurs at 1:37 a.m. EDT on Wednesday, 23 September. It is quite common for the group of seven stars which every child knows as the "Big Dipper" to be mistakenly referred to as a constellation. The Dipper is an "asterism", or an interesting grouping of stars, and occupies a region of the constellation Ursa Major, the great bear. It's association with a bear has been traced back to the Greeks whose mythology told of a she-bear that nursed the infant Zeus, according Giuseppe Maria Sesti's "The Glorious Constellations." Interestingly enough, numerous cultures on continents separated by great oceans have identified these same stars with the figure of a bear. A well known tale told by Native Americans involved a bear hunt with the hunters being represented by various stars in the constellations of Ursa Major and Bo”tes. Visitors to the regular monthly planetarium programs at Bear Branch Nature Center (reservation information: 410-848-2517) are often entertained with rich and entertaining folk tales from cultures of the world. While vacationing this summer in Wyoming I heard yet another Native American legend involving the Big Dipper as told by the Kiowa people who inhabited the region including the renowned Devil's Tower, a rock formation believed to be the core of an ancient volcano. Seven sisters and their brother were playing one day when the boy, who was crawling on all fours, was suddenly transformed into a bear. His fingers grew into claws and his body became covered in fur. The bear chased the frightened sisters to the magic stump of a great tree. The stump spoke, telling them to climb up. When they did the stump began to grow larger, and as the bear scored the bark with his claws the sisters were hoisted into the sky and transformed into the seven stars of the Big Dipper. What is interesting about this legend is that even though the bear is a central character, the figure of the bear is not included in the star pattern. In Great Britain the Big Dipper is viewed as a plough with the bowl forming the blade and the pan's handle forming the handle of the plough. During the fall harvest season the plough appropriately scrapes the northern horizon. To see this, look at the Dipper at the following times: midnight in early September, 11 p.m. at mid- month, 10 p.m. in late September, and 7 p.m. in early November. From Maryland's latitude the Big Dipper is up all night every night of the year. In fact it is up all day as well although we cannot see it. Stars and constellations that do not set are called "circumpolar". As the earth turns they appear to slowly revolve around Polaris, the north star, as if they were attached to it with a string. If you face Polaris the earth's rotation causes all stars to appear to revolve in a counter-clockwise direction. The motion is difficult to detect visually, but if you look at the Dipper again one or two hours later the position will appear to have shifted. Of course if your horizon is obstructed by buildings, trees, or hills, the Big Dipper might might not be visible as it skims the ground. The stars of the Big Dipper are of nearly equal brightness. Mizar, the central member of the three-starred handle, has a fainter companion star Alcor which sharp-eyed observers can see without optical aid. If you have trouble seeing it, then grab a pair of binoculars and try again. Your feedback is always appreciated. You may e-mail your comments to StarPointsUSA@yahoo.com.