The Stars of Summer
To us, who dwell in a world of change, the stars give the comfort of abidingness; they remain ever the same to our eyes and the teacher should make much of this. When we once come to know a star, we know exactly where to find it in the heavens, wherever we may be. A star which a person knows during childhood will, in later life and in other lands, seem a staunch friend and a bond, drawing him back to his early home and associations.
The summer is an enticing season for making the acquaintance of eight of the fifteen brightest stars visible in northern latitudes. Few midsummer entertainments rival that of lying on one's back on the grass of some open space which commands a wide view of the heavens, and there with a planisphere and an intermittently lighted candle with which to consult it, learn by sight, by name and by heart those brilliant stars which will ever after meet with friendly greeting our uplifted eyes. To teach the children in a true informing way about the stars, the teacher should know them, and nowhere in nature's realm is there a more thought-awakening lesson.
The Bright Stars of Summer
Leading thought—The stars which we see shining during summer evenings are not the same ones that we see during the winter evenings, except those in the polar constellations. There are eight of the brilliant summer stars, which we should be able to distinguish and call by name.
Method—Begin by the middle of May when the Big Dipper is well above the Pole-star in the early evening, and when, therefore, Regulus, Spica, Arcturus and the Crown are high in the sky. The others may be learned in June, although July is the best month for observing them. In teaching the pupils how to find the stars, again instruct them how to draw an imaginary straight line from one star to another and to observe the angles made by such lines connecting three or four stars.
Place upon the blackboard the figures from the chart (page 901), as indicated, leaving each one there until the pupils have observed and learned it. Then erase and place another figure. In each case try to get the pupils interested in what we know about each star, a brief summary of which is given. Note that the observations given in the lessons are for early in the evenings of the last of May, of June, and of early July.
Draw upon the blackboard from the chart (p. 901) the Pole-star, the Big Dipper, the line G and the Sickle shown just below the outer end of the line. Extend the line that passes through the pointers of the Big Dipper to the North Star backward into the western skies; just west of this line lies a constellation called the Sickle, and the stars that form it outline this implement. The Sickle has a jewel at the end of the handle, which is a white and diamond-glittering star called Regulus. It is a great sun giving out one thousand times as much light as our own sun, and this light reaches us in about one hundred and sixty years. The Sickle is part of a constellation called the Lion, and from which comes the shower of meteors which we see on the evening of November 13th. Regulus is seen best in Spring.
Place on the blackboard the Big Dipper, the Pole-star and the line E, Arcturus and the Crown. Extend the handle of the Big Dipper following its own curve for about twice its length and it will end in a beautiful, yellow star, the only very bright one in that region. It is a thousand times brighter than our own sun, but its light does not reach us for a hundred years after it is given off. Arcturus is supposed to be one of the largest of all the suns, having a diameter of several millions of miles. During the latter part of June and July it is almost overhead in the early evening.
Between Arcturus and Vega, but much nearer the former, is a circle of smaller stars that is called the Northern Crown, and which because of its form is quite noticeable.
Place on the blackboard the Big Dipper, the Pole-star, the line F and Spica. To find Spica draw a line through the star on the outer edge of the top of the bowl of the Big Dipper, through the star at the bottom of the bowl next the handle, and extend this line far over to the southwest, during the evenings of June and July. (See page 901) In August, this star sets at ten o'clock. Spica is a white star, and is the only bright one in that part of the sky. It is so far away from us that the distance has never been measured. Spica is in the constellation called the Virgin.
Place on the blackboard the Pole-star, the Big Dipper, the lines H and I and Vega with her five attendant stars, as shown in the chart. Teach that these stars are the chief ones in the constellation called The Lyre. To find Vega, draw a line from the Pole-star to the star in the Big Dipper which joins the bowl to the handle. Then draw a line at right angles to this (see chart lines H, I) and extend the line I a little farther from the North-star than is the end star of the Dipper handle; this line will reach a bright star, bluish in color, which can always be identified by four smaller attendant stars which lie near it and outline a parallelogram with slanting ends. Vega is the most brilliant summer star that we see in the northern hemisphere. It is a very large sun, giving out ninety times as much light as our sun; it is so far away that it requires twenty-nine years for a ray of light to reach us from it. Vega's chief interest for us, aside from its beauty, is that toward it our sun and all its planets, including our earth, are moving at the rate of thirteen miles per second.
Add to the last diagram on the blackboard the line E, Arcturus, the line B and Antares. To find this star, draw a line half way between Arcturus and Vega from the Pole-star straight across the sky to the south, and just above the southern horizon it will point to the glowing star, Antares, in the constellation of the Scorpion. Also a line drawn at right angles to the line connecting Altair with its companions and extending toward the south will reach Antares. Late June and July about ten o'clock in the evening is the best for viewing this beautiful star. An interesting thing about Antares is that, although it is red, it has, whirling around it, a companion star which is bright green.
Deneb, or Arided (den'-eb; a'-ri-ded)
Erase from the last diagram Antares and the line B. Add to it the lines C and D making a right angle at Deneb; and the Cross—the head of which is Deneb, the foot ending near the letter on line L. This star is at the head of the Northern Cross, which is a very shaky looking cross and appears upside down in the eastern skies during the evenings of June and July. Deneb is white in color and is a very large sun, because it seems to us a bright star although it is so far away from us that the distance has never been surely measured; but it has been estimated that a ray of light would need at least three hundred and twenty-five years to reach us from Deneb. It and the cross are a part of the constellation of Cygnus, or the Swan.
Add to the last diagram on the board the lines L, K, Altair and its two attendant stars and the Dolphin. Emphasize the fact that Altair marks the constellation of Aquila, or the Eagle. This beautiful star is easily distinguished because of its small companions, one on each side, all three in a line. The three belong to a constellation called the Eagle, and may be seen in early evening from June to December. Altair, Deneb and Vega form a triangle with the most acute angle at Altair. (See chart L, K.) Just northeast of Altair is a little diamond-shaped cluster of stars called the Dolphin, which is a good name for it, since it looks like a dolphin, the fifth star forming the tail. It is also called Job's Coffin, but the reason for this is uncertain, unless Job's trials extended to a coffin which could not possibly fit him. If the line C on the chart drawn from the Pole-star to Deneb be extended, it will touch the Dolphin. Altair is always low in the sky; it is a great sun giving off nearly ten times as much light as our own sun; light reaches us from it in fifteen years.