LABORATORY MANUAL 9 



to it as it. Good laboratory work is worthy of the best 

 expression the pupil can give, and good habits of work are 

 an aid to advanced study in any subject. 



EXERCISE I (Textbook 5) 



THE NORTHERN SKY IN SEPTEMBER 

 (OR ANY OTHER MONTH SELECTED) 



APPARATUS: Compasses, hard pencil, sheet of notebook 

 paper. 



NECESSARY CoNDfriONs: A clear evening without bright 

 moonlight; state the hour of observation. 



On the front page of the notebook sheet make a circle 

 of three-inch radius. At the center place * and mark it 

 P (Pole Star) . Draw a dotted-line vertical diameter through 

 the point (*). Draw a horizontal line across the page 

 touching the lower part of the circle at the' diameter's in- 

 tersection. Letter the horizontal line H at both ends and 

 place N at the diameter. 



HH is a part of the northern horizon, N is the north point, 

 and the line PN is part of the celestial meridian. If the 

 line were continued upward on the sky, it would pass through 

 the zenith and down to the south point on the horizon. 



Within the circle, place the groups of stars you observed 

 in the northern sky. Indicate the brighter stars by *, the 

 fainter ones by X . Locate carefully the position of each 

 group with relation to the Pole Star and to the celestial 

 meridian. Estimate carefully the space occupied by each 

 group. 



RESULTS 



1. Write neatly the name of each constellation under the 

 proper group on your map. (Consult the textbook on 

 " Stars Visible all the Year," p. 17.) 



2. Which group as a whole is nearest the Pole Star? 



3. Which group is highest above the horizon? 



