Appendix D

STAR TESTS FOR EYESIGHT

There are a number of stars which are considered to be good tests for the seeing power of the eyes. The faint stars of the Pleiades are a fine test of this kind; but usually these tests are double stars and while one will be bright and easily seen its companion will be very faint. The test is to see the faint one, and if you can see it you may consider you have very good eyesight.

Eyesight tests are given on the following pages:

Page 11--Mizar and Alcor 34--Spots on the Sun 94--Grimaldi on the Moon 119--Nebula in Orion 150--Epsilon in Lyra 150--Pleiades 182--Alpha and Beta in Capricornus

APPENDIX E

MAGNITUDES OF STARS

There are not nearly as many stars in the sky as you might at first suppose. The stars are divided into magnitudes, that is, according to their brightness. Stars of the first magnitude are the brightest stars; stars of the second magnitude are second brightest, and so on. The total number of stars which can be seen with the naked eye on any one night in the United States is probably not more than 3,000. The following table gives the number of stars of the different magnitudes up to and including the sixth:

Magnitudes Number of Stars 1st 20 2nd about 65 3rd about 200 4th about 500 5th about 1,400 6th about 5,000

APPENDIX F

FIRST MAGNITUDE STARS

The brightness of a star is known by its magnitude. A star of the first magnitude is one of the 20 brightest stars, and is 2½ times as bright as a star of the second magnitude; a star of the second magnitude is 2½ times as bright as a star of the third magnitude; and so on. A star of the sixth magnitude can just be seen with the naked eye on a clear night when there is no Moon.

Fifteen of the twenty first magnitude stars can be seen in our latitude, and these are:

& OF & OF STAR CONSTELLATION

1. Sirius, the Dog Star, in Canis Major 2. Capella “ Auriga 3. Arcturus “ Bootes 4. Vega “ Lyra 5. Rigel (β) “ Orion 6. Procyon “ Canis Minor 7. Betelgeux (α) “ Orion 8. Altair “ Aquila 9. Aldebaran “ Taurus 10. Spica “ Virgo 11. Antares “ Scorpius 12. Pollux “ Gemini 13. Regulus “ Leo 14. Deneb “ Cygnus 15. Fomalhaut “ Piscis Australis

APPENDIX G

CONSTELLATIONS HAVING FIRST MAGNITUDE STARS

The following important constellations are not described in the foregoing chapters of this book. They can be found, though, without trouble, since a star of the first magnitude is located in each.

Canis Major, the Big Dog, is a winter constellation, and can be seen on your meridian at 9 o’clock P. M. in February. Look for it in the southern sky and you will quickly find it because of the dazzling brightness of Sirius, the Dog Star.

Bootes (pronounced Bo-ō´-tes), the Bear Leader, is a summer constellation, and can be seen on the meridian at 9 o’clock P. M. in June. It is to the north of the ecliptic, or path of the Sun. It lies between a crown of stars and Virgo. You can’t miss it, for midway is Arcturus, a red star of the first magnitude.

Lyra, the Lyre.--Is a summer constellation, and can be seen on the meridian at 9 o’clock P. M. in August. Look for it almost overhead, and you can’t mistake it, for three bright stars, of which Vega is one, form a triangle.

Canis Minor.--The Little Dog: is a spring constellation, and can be seen on the meridian at 9 o’clock P. M. in March. It lies to the south of the constellation of Gemini, the Twins, and Cancer, the Crab. In it you will see Procyon, the Little Dog Star.

Aquila, the Eagle.--Is a summer constellation, and can be seen on the meridian in August. Look for it south of Lyra, and far to the west of Pegasus. The star that put Aquila on the map is Altair.

Cygnus, the Swan.--Is also a summer constellation, and can be seen on your meridian at 9 o’clock P. M. in September. You will find it north of Pegasus and east of Lyra, and in it you will see the Northern Cross clearly traced out with seven stars, the brightest one being Deneb, a first magnitude star.

Piscis Australis, the Southern Fish, is an inconspicuous constellation far south of the Equator. Fomalhaut, its brightest star comes only 20 degrees above our horizon and must be looked for when it is near the meridian--about 9 o’clock P. M. in October.

APPENDIX H

COLORED STARS

You can easily notice that the stars differ in color. The following list gives the colors of a few of the brighter stars:

WHITE STARS: Sirius, Regulus, Vega. BLUE STARS: Rigel and Spica. RED STARS: Aldebaran, Antares, and Betelgeux. GREEN STARS: B Librae. YELLOW STARS: The Sun, Arcturus, and Capella.