220 



THE GUIDE TO NATURE 



Triang-ulum. In the North you have 

 the Dippers and Cassiopeia, and in no 

 time you have located half a dozen con- 

 stellations ; a little more effort and you 

 add the others. Not very difificult is it? 

 And vet this simple bit of knowledo-e, 

 which it is a pleasure and a recreation 

 to acquire, is fundamental, and paves 

 the way for telescopic work of a high 

 order of scientific value, a knowledo-e 

 of which is almost as easily acquired. 



Even an opera glass is of value, as 

 many stars that present enigmas and 

 astrophysical problems can be studied 

 with the simplest optical means, and 

 observations made with them that 

 have scientific value. 



Here then in this great laboratory 

 of the starry night science calls vou to 

 do your bit, and offers you a splendid 

 opportunity of spending your leisure 

 time profitably. 



Even if you go no farther than 

 acquiring a knowledge of the constel- 

 lations, you have done something 

 worth while, for aside from the pleas- 

 ure of knowing the stars intimately, 

 and being able to call them by name, 

 you have in them a never failing com- 

 pass which may be of great service to 

 you, and which is an essential bit of in- 

 formation for the Bov Scouts to ac- 

 quire. To my mind the qualifications 

 of first-class Scouts should include a 

 knowledge of all the constellations, for 

 you cannot always see the North Star, 

 while other stars may be visible from 

 your point of view. After all a know- 

 ledge of the constellations is po easily 

 acquired that everv one should pick up 

 this useful bit of knowledge. 



When you know the geographv of 

 the heavens, and have observed many 

 of the beautiful colored double stars, 

 the brighter nebulae and star clusters 

 with your opera glass, you will long 

 to possess a telescope, and it is one of 

 the best investments you can possiblv 

 make, for unlike most things it does 

 not depreciate in value as time goes 

 on, and it yields rich dividends in plea- 

 sure and mental profit. I may say here 

 that small telescopes are not nearly as 

 expensive as many people think, for 

 you can often pick up a glass of three 

 inch aperture, which is admirable for 

 ordinary telescopic purposes, in a sec- 

 ondhand shop for comparatively little. 

 Many optical stores offer rare bargains 

 in secondhand telescopes, which are 



quite ^ as good as new, practically 

 speaking. 



When you have your glass you will 

 first wish to observe the moon, planets 

 and the hosts of wonders that await 

 your inspection, but after a short time 

 when you have surveyed these marvel- 

 lous sights your interest will begin to 

 wane a bit, and then it is that science 

 makes its appeal to you, and urges you 

 to devote your spare time and valuable 

 glass to advance our knowledge of the 

 universe. 



We want to know why several hun- 

 dred of the stars fluctuate in bright- 

 ness. Why are they sometimes bright 

 and sometimes dim? Why is there ir- 

 regularity in their variation in bright- 

 ness, faintness, range and period? 

 Surely this is a wonderfully fascinat- 

 ing problem to investigate, and it is in 

 the power of the possessor of a small 

 telescope to take an active part in the 

 determination of the law that governs 

 these mysterious stars. 



The method of observing variable 

 stars is extremely simple, any high 

 school boy can comprehend the details 

 of the method employed. It is purely 

 a case of constant practice in observ- 

 ing, and the eye soon becomes trained 

 to the work so that accurate and valu- 

 able observations can be quickly and 

 easily made. It is merely a question 

 of recording what you see, and surely 

 any one can do this with a little prac- 

 tice. 



Now I have told you how you can 

 aid science if you only will. I have as- 

 sured you that the work is not at all 

 difficult, and that any high school boy 

 or girl or Boy Scout can engage in such 

 work, and I have endeavored to make 

 you see that in telescopic work there 

 is a mine of enjoyment within your 

 grasp. 



It will be a pleasure to hear from any 

 one who reads this who is willing to 

 enter our laboratory and co-operate 

 with us, and such persons are assured 

 a hearty welcome as members of the 

 American Association of Variable Star 

 Observers. It will be a privilege to as- 

 sist all who wish to know more about 

 this useful and interesting work, and 

 who wish to aid science by observing 

 the fascinating and mysterious vari- 

 able stars. 



