APPENDIX B

Figures.—When explaining the positions and forms of things, it is often necessary to use certain terms and figures, that is to say, lines which are either real or imaginary, but which can be drawn on paper. [See Fig. 185].

(1) A straight line is, of course, a line which runs uniformly in the same direction, and which is regular and without curves. A straight line is the shortest distance between two points. (2) When we say that lines are parallel, we mean that they lie so that every part of each is equally spaced from the other. (3) A line is horizontal when it is parallel with the level surface of the Earth under it. (4) A line is perpendicular to the surface of the Earth when it is plumb, that is, in a line with the center of the Earth. (5) A vertical line generally means a plumb line. (6) A right angle is formed when a vertical, or a perpendicular, line meets a horizontal line. (7) A circle is a curved line, all points of which are equally distant from its center. Circular means round like a circle. (8) By diameter is meant a straight line drawn from one side, or half of a circle, to the opposite side through its center. (9) The radius of a circle is a straight line drawn from the center of a circle, or a ball, to its circumference. (10) A ring is a disk or object having a circular hole cut in its center. (11) An arc of a circle is a part of a circle. (12) A quarter circle is, of course, the one-fourth part of a circle. (13) A tangent is a line which touches a curve but does not cut it. (14) An ellipse is an oval figure, drawn on a plane surface. (15) The equator is a circle which divides the Earth or other ball into equal parts, and is 90 degrees from the north and south poles. (16) The ecliptic is a circle round the Sky in whose plane lies the orbit of the Earth.

Fig. 185.—Geometrical Figures.

APPENDIX C
THE GREEK ALPHABET

Many of the brighter stars have names, as Aldebaran, Capella, Sirius, etc., but astronomers now indicate the stars of a constellation by the letters of the Greek alphabet. The usual method is to call the brightest star of a constellation α, that is, Alpha, the next brightest β which is Beta, and so on, but sometimes the stars are lettered in order of position in the sky.

The following is the Greek alphabet:

αAlphaνNu
βBetaξXi (Zi)
γGammaοOmicron
δDeltaπPi
εEpsilonρRho
ζZetaσSigma
ηEtaτTau
θThetaυUpsilon
ιIotaφPhi
κKappaχChi
λLambda ψPsi
μMuωOmega

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
2ndabout65
3rdabout200
4thabout500
5thabout1,400
6thabout5,000

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:

NAME OF STAR NAME OF CONSTELLATION
1.Sirius, the Dog Star,inCanis 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:

APPENDIX I
DOUBLE STARS

When two stars are very close together they form what is called a double star, but double stars of which the two components are really near together in space and revolve around each other usually cannot be resolved, that is separated, into two stars without the aid of a telescope.

The North Star; Rigel, Castor; Procyon and Sirius, are all famous double stars.

APPENDIX J
VARIABLE STARS

A variable star is one whose brightness changes from time to time. A great many variable stars are known, but very few of them can be seen with the naked eye. There are different reasons given for a star varying in brightness. Our Sun is a variable star, and we are told that this is due to his spots. Another type of variation is perhaps produced by pulsations—the star periodically expanding and contracting. Again a double star formed of two bright stars which revolve round each other, as many double stars do, may eclipse one another, and this would cause a change in brightness. Here, then, are three good reasons for a star being variable.

The following are a few of the variables which can be seen with the naked eye:

APPENDIX K
INVISIBLE OR DARK STARS

Stars are born, live and die, just like human beings. All the stars, including the Sun, are either in the process of making, are at their brightest brilliancy, are dying out, or are cold and dead or have not yet become bright.

Procyon and Sirius is each attended by a comparatively dark companion. Procyon and Sirius both move slowly back and forth a short distance in the sky and this motion was attributed to the pull of satellites long before these bodies were discovered with the telescope.

APPENDIX L
THE EQUATION OF TIME

TABLE OF THE EQUATION OF TIME
Day of
Month 		JanuaryFebruaryMarchAprilMayJune
m s m s m s m s m s m s
 1S  3 31 S 13 44 S 12 37 S 4  6 F 2 56 F 2 30
 6S  5 49 S 14 15 S 11 33 S 2 37 F 3 27 F 1 41
11S  7 59 S 14 27 S 10 19 S 1 14 F 3 45 F 0 44
16S  9 49 S 14 19 S  8 57 F 0  4 F 3 48 S 0 18
21S 11 24 S 13 52 S  7 28 F 1 12 F 3 28 S 1 23
26S 12 39 S 13 10 S  5 56 F 2 10 F 3 15 S 2 27
31S 13 35 S 12 13 S  4 24 F 2 56 F 2 39 S 3 38
Day of
Month 		JulyAugustSeptemberOctoberNovemberDecember
m s m s m s m s m s m s
 1S 3 28 S 6 10 S  0  6 F 0  8 F 16 18 F 11  3
 6S 4 24 S 5 46 F  1 31 S 11 41 F 16 17 F  9  3
11S 5 11 S 5  8 F  3 13 F 13  4 F 15 56 F  6 51
16S 5 46 S 4 15 F  4 58 F 14 16 F 15 13 F  4 30
21S 6  9 S 3  9 F  6 45 F 15 13 F 14 10 F  2  2
26S 6 11 S 1 51 F  8 29 F 15 54 F 12 45 S  0 28
31S 6 12 S 0 24 F 10  8 F 16 16 F 11  3 S  2 55

As we have seen in [Chapter X] every day of the year is exactly 24 hours long by our clock time. The time by the Sun is usually either ahead or behind local clock time. The difference between clock time and Sun time is called the equation of time, and a table to show how many minutes and seconds the Sun is fast or slow, according to clock time, is given above, taken from “The New Astronomy,” by Professor Todd, who has kindly permitted me to use it here. In the table S means that the Sun is slow, that is, that the Sun does not cross the meridian until after the clock shows noon, and F means that the Sun is fast, that is, that the Sun has crossed the meridian before the clock shows noon. m means minutes, and s means seconds above the figures.

The table gives the average values of the equation of time, which may differ by a few seconds from the values for any particular year.

APPENDIX M
THE KULLMER STAR FINDER

The star finder shown in the picture was invented by Dr. C. J. Kullmer, of Syracuse, N. Y., and has been highly praised by many great astronomers.

Fig. 186.—Kullmer Star Finder.

You should own one if possible, for you do not need to know anything about the stars to operate it. It is mounted on the principle of a big telescope, but it is a naked eye instrument, an arrow taking the place of the telescope.

The finder is placed on a table, or other level surface, with the dial facing north. Then the pointer and dial are set for the day and hour when you want to find the position in the sky of a certain constellation. The indicator is turned to the name of the constellation on the dial, and this also tells the direction to set the arrow.

This is all there is to it and the arrow points right at the group of stars you want, whether they are above the horizon or not.

The finder can be used for many purposes, and it is a wonderful aid in making out in the sky the path of the stars, Sun, Moon and planets, and when they rise and set. In fact, it is a complete observatory on a small scale. Its cost is only $5.00.

APPENDIX N
THE ELLIS SEASONAL TWILIGHT CHART

A useful chart, designed by Miss E. Rebecca Ellis, of Wellesley College, Wellesley, Mass. It makes clear the changes in the lengths of the day, the phenomena of the seasons, etc. Its price is $1.00.

APPENDIX O
THE CAMP FIRE SKY MAP

This map, prepared by Prof. R. S. Dugan of Princeton University, shows the constellations as far south as the Southern Cross and is adjustable for the time of night, date, and for the latitude. Full instructions are given for its use. It is used in many schools and colleges. It is sold by the Camp Fire Stores Co., price 19 cents.

DEFINITIONS OF SOME WORDS AND
TERMS USED IN THIS BOOK

Action. The way in which a thing works.

Affect. To act upon; to change; to be moved or influenced by.

Almanac. A pamphlet or book containing tables showing the days of the year; also the time the Sun and Moon rise and set; the conjunctions, eclipses and other information concerning the things in the sky. The word almanac is supposed to be derived from the Arabic article al and the verb manac, which means to count.

Angular measurements. [See Appendix B].

Aphelion. The point where a planet or a comet is farthest away from the sun.

Apparent. To seem real. The daily motion of the Sun round the Earth is only apparent, for we know it is the Earth which turns round on its axis instead.

Arc. [See Appendix B].

Arc of circle. [See Appendix B].

Aspect. (1) Any curious appearance of an object, especially if the object changes in appearance. (2)The figure formed by a planet with the stars of the constellation which it is in.

Astrologer. One who forecasts the life of a person on the supposition that the stars control it.

Astronomer. One who is skilled in seeing the stars and who knows them.

Atom. A very small particle of matter. See Molecule; Matter.

Attract. To pull toward. The attraction of the Sun and the Earth for each other is due to gravitation.

Attraction. A force which pulls one body to another.

Attraction of Gravitation. A force which pulls all bodies to each other.

Auditory nerve. A nerve that carries the impressions of sound which reach the ear to the brain.

Aurora borealis. The Northern Lights. A glowing light effect which takes place in the Arctic Circle. It can often be seen from our Northern States and sometimes from the Southern States. The same kind of lights appear in the Antarctic Circle. These Southern Lights are called Aurora Australis.

Axes. Plural of axis.

Axis. An imaginary line on which a body turns.

Axis of rotation. An imaginary line round which anything turns or spins.

Axle. A wood or metal rod on which one or more wheels turn, or it may turn with the wheel or wheels.

Badge of merit. A badge awarded by the organization of Boy Scouts to members who can show a certain amount of skill in doing certain things. [See Appendix A].

Band. (1) A flat strip of any material, or (2) such a strip whose ends are joined together.

Beam. Rays of light which are parallel. See Ray.

Bearing. (1) A piece of metal, or a bit of agate or other jewel, on which a pivot, spindle or shaft turns. (2) A direction as found by the Sun or stars, or by the compass, sextant or other means.

Body. Any separate and distinct amount of matter when held together. The Sun and Moon are heavenly bodies.

Degree. (1) The 360th part of a circle. (2) Indicated by this sign °.

Device. (1) An apparatus or instrument or any part thereof. Any arrangement for producing a given result.

Diagram. A sort of shorthand picture of an apparatus or part of an apparatus. It is used to show in the simplest and clearest manner the construction of an apparatus.

Diameter. [See Appendix B].

Direct line. A straight line.

Disk. (1) A circular plane or flat surface. Since the Sun, Moon and planets seem to be flat their surfaces are called disks. (2) Flat and circular like a coin.

Dog days. So called from the fact that Sirius, the Dog Star, rises at the same time as the Sun.

Ecliptic. [See Appendix B].

Elastic. (1) A body that will stretch and return to its original size. (2) A thin piece of rubber.

Ellipse. [See Appendix B].

Equator. [See Appendix B].

Equatorial. Having to do with or affected by the equator.

Equatorial telescope. A telescope so mounted that its principal axis is parallel with the axis of the earth and moved by clockwork so that it will follow a star.

Evening Star. A planet which can be seen in the west just after the sun sets.

Fixed. (1) Fastened securely. (2) The stars are called fixed because they never seem to change their positions.

Forecast. A prediction of some future event. A forecast may be founded on fancy or on fact. A horoscope of a person is a forecast based on the fancy of an astrologer. A weather forecast is founded on the action of a barometer, and even then the forecast is uncertain enough. Forecasts of the time of eclipses, the return of comets and the like are founded on cold scientific facts and hence come true at exactly the calculated time.

Frequency. How often an event occurs.

Gas. That form of matter which is like air. Some gases remain in the gaseous state at ordinary temperatures. Gases have a tendency to expand without limit. See Vapor.

Generate. To produce. To set up; as a battery generates a current; the Sun generates power.

Gravitation. The force which attracts all bodies near the Earth to it and all bodies to each other.

Heavens. The sky. The space as far as the eye can see about the Earth. The space in which the stars and their planetary systems move.

Horizontal. [See Fig. 185].

Horoscope. A forecast of the future of a person made by an astrologer who pretends to read the future from the aspect or position of the planets and stars.

Hyperbola. [See Fig. 129].

Hypothesis. [See Idea].

Idea. A notion of a plan or scheme which may be more or less vague. Supposition. A clearer conception of a plan or scheme which is based on such facts as may be thought of. Hypothesis. A plan or scheme assumed to be true and carefully reasoned out from all the facts obtainable. Theory. A plan or scheme which has been proved true by experiment, examination or comparison.

Illusion. An image which deceives the eye. The other senses can also be deceived by illusions.

Impact. Coming together of two objects.

Impress. To form on, or to affect, as light waves impress a dry plate.

Indicate. To show. To point out.

Indicator. That which points out or shows something.

Limb. The edge of the Sun, Moon or Planets.

Lore. Learning on any subject.

Lunar. Of, or having to do with the Moon.

Magnetic lines of force. The direction of the force of magnetism acting in and around a magnet.

Magnetic storm. The Earth is a great magnet and sometimes when sun spots of unusual size or numbers appear, the magnetic lines of force of the Earth are violently affected. This is called a magnetic storm.

Mass. (1) Amount of matter. (2) A lot of molecules or particles of matter brought and held together.

Matter. The substance of which a thing is formed. A molecule of matter is made up of atoms, and a mass is a lot of molecules held together by some attractive force.

Mercury. (1) The name of the planet nearest the Sun. (2) A silver white liquid metal.

Molecule. The smallest part of matter that can exist separately without the substance it forms being destroyed.

Morning Star. A planet which can be seen in the east just before the Sun rises.

Morse code. A telegraph code of dots and dashes invented by Samuel F. B. Morse. The Morse Code is used for telegraph and heliograph signaling.

Motion. Anything that changes position. There are two kinds of motion (a) simple motion and (b) compound motion. Simple motion can be either translated or rotary, while compound motion is both translated and rotary, so that while a body is being translated, or moved through space, it is also rotating on its axis. The Sun and planets, then, have compound motions.

Nature. Everything contained in space that has not been shaped by human hands.

Nautical almanac. The American Nautical Almanac is a book of the stars published by the Bureau of Navigation of the United States. It is published three years in advance and is sold by the Superintendent of Documents, Washington, D. C., at 30 cents per copy. This is designed chiefly for the use of navigators of ships. It gives the exact positions of the Sun, Moon and planets and much other astronomical information. It is based upon the calculations made by the United States Naval Observatory; these are printed in the Nautical Almanac, and on this all other almanacs are based.

Northern lights. See Aurora Borealis.

Obscured. Hidden from sight.

Official Handbook of the Boy Scouts. A book published by the organization of Boy Scouts and which contains the rules and regulations of that organization and the requirements they must meet in order to win merit badges.

Offset. To equal; to balance.

Opposition. [See Appendix].

Optic Nerve. The nerve that carries the impression of light received by the eye to the brain.

Orbit. The path followed by a body. Atoms have orbits as well as the stars. The paths followed by planets and comets round the Sun.

Parabola. [See Fig. 129].

Parallel. [See Appendix B].

Particle. A bit of matter. A particle may be a bit of matter which can be seen or it may mean an amount so small that it cannot be seen.

Pencil. A group of rays from the same source of light. See Beam. See Ray.

Pendulum. A body suspended from a fixed point and free to swing.

Perihelion. The point where a planet or a comet is nearest the Sun. As the orbit of a planet is an ellipse and the Sun is in one of the foci—that is near one end—a planet comes nearest to the Sun when at this end of the ellipse; and when the planet is at the other end of its orbit, it is farthest away. See Aphelion.

Period. A certain interval of time which is marked by a repeated occurrence. The period of the Earth round its axis is about 24 hours. Its period around the Sun is 365¼ days.

Periodic. Recurring regularly; as a periodic comet.

Perpendicular. [See Appendix B].

Phase. One of the peculiar aspects of a heavenly body; as the phases of the Moon, or the phases of Venus.

Pivot. A pin, spindle or shaft on which a wheel, lever or device rotates or is rotated.

Plane. A level surface, as a table top.

Point. A sharp end. A starting place.

Pores. Minute spaces which separate the molecules of a substance.

Position. The place of a thing when compared to the places of other things.

Precede. To go ahead of. That which is before.

Precession. The act of going ahead or preceding. When a revolving body such as a spinning top or the Earth is acted upon by forces which tend to change the direction of its axis. This change in the direction of its axis is called precessional motion. The pole of the equator of the Earth makes a complete turn round the pole of the ecliptic in a little over 25,000 years and this change in the direction of the axis of the Earth causes the points of the equinox, that is the places where the ecliptic and the equator cross each other to move slowly from west to east and this is termed the precession of the equinoxes.

Prediction. To foretell; to forecast. Predictions may be based on fancy or founded on fact.

Principal. The chief one; the most important.

Principle. The cause of a result. That on which a thing is based.

Process. (1) The way of working. (2) The course of procedure.

Produce. In astronomy the word produce means the lengthening of a line. It is a mathematical term.

Protractor. [See Fig. 98].

Quarter circle. [See Appendix B].

Ray. (1) A single line of light or heat. (2) The path of light and heat.

Relative position. The position of a thing when compared with the position of something else. See Position.

Revolution. The turning of a thing completely round on its axis.

Revolve. (1) To turn completely round a circle. (2) To turn on an axis, as a top, or the Earth.

Rigid. Firm, that which cannot be easily moved out of its place.

Ring. [See Appendix B].

Rise. To come into sight above the horizon, as the Moon rises.

Rotate. To turn completely round on an axis like a top or the Earth.

Rotary. Turning completely round on an axis, like a top or the Earth.

Roughly. Not exactly; nearly enough for practical purposes.

Schedule. (1) A tabulated statement giving items concerning a subject. (2) A timetable of any kind.

Seeing. To look at. The word seeing in starcraft means to observe the stars. Good seeing is to observe the stars when the atmosphere is perfectly clear.

Seems. Something which apparently is true and yet is not necessarily true.

Sensation. The action of one of the senses when excited by some change in matter. Light falling on the retina of the eye produces the sensation of light and color in the brain.

Set. To sink from sight below the horizon; as the Sun sets.

Sight. The power to see. See Sighting.

Sighting. To get the eye and two other objects, such as a telescope and a star, in a line, as to sight Jupiter with a telescope.

Sign. A mark, figure or letter which astronomers have agreed to use to represent certain stars, aspects of stars, parts of the zodiac, etc.

Solar. That which is of, or has to do with the Sun.

Spring stars. The stars which can be seen best during the spring months.

Star chart. A map of the positions of the stars.

Starcraft. Useful knowledge of the stars. Skill shown in making the stars serve useful purposes.

Star finder. A device of any kind which will enable an unskilled person to find the planets or constellations.

Star-lore. Learning concerning the mythology of the stars.

Summer stars. The stars which can best be seen during the summer months.

Supposition. [See Idea].

Tangent. [See Appendix B].

Tangent line. [See Appendix B].

Telegraph code. The alphabet of dots and dashes.

Test. To try out. To examine, compare or make an experiment which will give a needed proof.

Theory. [See Idea].

Thumb tack. A short, thin, sharp-pointed tack with a large flat head which permits it to be easily pushed into a board with the thumb. It is used by draftsmen for fastening paper to drawing boards.

Tilting. Leaning from a vertical or plumb line. The axis of the Earth is tilted from the perpendicular 23½ degrees; this throws its equator out of plane with that of the sun, and the circle through the Earth that is in plane with the Sun is called the ecliptic.

Transparent. Said of any substance through which light can pass easily. Anything that may be seen through.

Twinkle. To blink. To flash with varying brightness. The twinkling of stars is caused by the atmosphere.

Uniform. Being the same all through or all along.

Vapor. A gas produced from a liquid or a solid and which returns to its original form at ordinary temperatures. See Gas.

Vertical. [See Appendix B].

Vibration. A to-and-fro movement, as the vibration of a particle of matter. A constant to-and-fro movement over the same line.

Visible. That which the eye can see.

Wane. To gradually grow smaller. Said of the Moon.

Wax. To gradually grow larger. Said of the Moon.

Winter Stars. The stars which can best be seen during the winter months.

Wireless Messages. Messages which are sent and received by wireless telegraph stations.

Wireless system. An apparatus for sending and receiving messages by wireless telegraph.

Your meridian. The line running due north and south in the sky directly over your head. A meridian of this kind is called a celestial meridian.

Zodiacal lights. A faint glowing light which may be seen above the western horizon just after twilight during the clear evenings of winter and spring. It can also be seen just before daybreak during the clear mornings of summer and autumn.