Yet even these cannot be seen at the same time but must be viewed from different parts of the earth's journey around the sun.
These brightest stars, which are called first magnitude stars, should be among one's first star acquaintances, for they serve conveniently as guides to locate the other stars, which are also classified according to magnitudes. The second, third, fourth and lesser magnitudes are each progressively two and a half times lower in the scale of brightness. The smallest stars discernible to the unaided eye of ordinary vision are stars of the fifth magnitude, although a sharp eye can discern those of the sixth and even of the seventh magnitude. All below this are telescopic stars. With a 60-inch reflector 219,000,000 stars are visible. The Mount Wilson 101-inch telescope brings the number up to 319,000,000. Stars are most dense in the region of the heavens called the Milky Way. Sir William Herschel observed 116,000 go past the field of his telescope in a quarter of an hour while directed at the densest part of the Milky Way.
This vast collection of stars differ not only in brightness but also in color.
The colors of the stars are brought out most vividly in the telescope if the observer knows just where to look for those which are the most pronounced. Some of the large stars are characterized by the most exquisite coloring,—which is sometimes further enhanced, as a glass will reveal, by a charming companion of a flamboyant or a delicate hue. Some of these "companions" are green, blue, orange, purple, gray, maroon and other colors, but such gayety is the exception rather than the rule. About three-fourths of the stars are white or bluish-white and nearly one-fourth of them are varying shades of yellow. The star Arcturus is of the deepest shade of yellow while the star Spica is so exceedingly white that poets and writers from the earliest times have spoken of the "purity" of its rays.
Although every star visible to the unaided eye may be identified by a Greek letter or a number, most of the brightest stars have individual names.
These individual names were given by the Arabian astronomers who nurtured astronomy through the Dark Ages when this science was almost forgotten by the rest of the world. These odd names have a certain appeal and many of them possess rippling musical qualities which add to the plain word as twinkles add to the star. It is a pleasure to say 'Capella,' or 'Antares,' when we see the gleam of the "Shepherd's Star," or the glow on the "Heart of the Scorpion"; or to call such jewels as shine on "Orion's Belt," 'Mintaka,' 'Alnilam' and 'Alnitak.' After the introduction one naturally takes a particular interest in 'Capella,' or 'Antares,' or 'Mintaka,' or 'Alnilam,' and continues to refer to it familiarly by name.
Each star not only attains a certain charm and individuality by having its own particular name, number, magnitude, color and pathway, but it also forms a part of a highly interesting group called a constellation.
On a clear night points of starlight seem to fairly fill the sky, yet it will be found, on careful examination, that the brightest of them often seem to be assembled together in a very picturesque manner, forming the outlines of figures such as the Dippers, the Crown, the Cross, the Sickle or the Lyre. Since these designs unfailingly deck the heaven's dome at the same place, hour and season each year, there is not the hopeless confusion among the stars that the novice might think from his occasional glances at the sky.
These star groups, or constellations, were probably first noted and named in Chaldea where the ancient shepherds amused themselves by tracing their heroes among the stars. One can well imagine the hold that these dream-pictures would have on a lonely shepherd as he wandered about the solitudes of the hills and gazed through the quietness of the night at the distant stars. For long ages these stories were told by one shepherd to another and so vivid were their fancies and so keenly were they enjoyed that they made an indelible impress upon the folk-lore of other nations and in this manner have been carried down to the present day.
The stars are self-luminous, like our sun,—indeed, the stars are distant suns, and the sun is a nearby star.