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.