338 



HOW TO OBSERVE THE HEAVENS. 



early part of the night. The stars &, *, *, which form the belt, being upon the 

 celestial equator, rise each evening at six o'clock precisely at the point of the 

 horizon which is due east, and at nine o'clock the constellation is elevated 

 midway between that point and the meridian. 



If a line be imagined to be drawn in the direction of the belt, and continued 

 both ways, east and west, it will pass a little north of the splendid star Sirius 

 (S), in the constellation of Cams Major, commonly called the Dog-star, on 

 the east, and a little south of another brilliant star, Aldebaran (A), on the 

 west. This latter star forms the eye of the zodiacal constellation Taurus. 

 Other stars in the constellation of Canis Major are represented at b c d. 



If a line be imagined to be carried from Sirius (S), in a direction perpen- 

 dicular to that which passes through the belt of Orion, it will conduct the eye 

 to the bright star Procyon (P), in the constellation of Canis Minor, which 

 is a star of the first magnitude, with one of the third magnitude near it. 



If a line be conceived to be drawn from Rigcl (ft), through y, and carried 

 upward, it will pass a little east of a bright star of the second magnitude (E), 

 in the foot of the constellation Auriga. 



If a line be imagined to be drawn from « through *■> and carried downward, 

 it will pass through another bright star (C), of the second magnitude in the 

 constellation Columba. 



The stars Sirius (S), Procyon (P), and Aldebaran (A), are all of the 

 first magnitude, and very splendid objects. Sirius, however, is not only the 

 most magnificent of these, but is the brightest star in the firmament. This 

 star was frequently submitted to telescopic examination by the late Sir William 

 Herschel, with the extraordinary optical powers which that observer com- 

 manded, and he relates that when it approached the field of view of the forty- 

 feet telescope, the effect resembled the approach of sunrise, and when the 

 glorious object entered the field of view the splendor was so overpowering that 

 he was obliged to protect the eye by a colored glass ! 



Dr. Wollaston calculated that this star must be equal to fourteen suns like 

 that of our system. This calculation, however, was founded on the supposi- 

 tion that the star is much nearer to us than it is now known to be, and the 

 splendor of the object has therefore been greatly underrated ! 



In the constellation of Orion are a considerable number of stars under the 

 third magnitude, not represented in the diagram, (p. 357), many of which, when 

 examined by powerful telescopes, prove to be double stars ; besides which is 

 found in the sword the most remarkable nebulae in the firmament, which we 

 shall hereafter notice more fully. 



If a line drawn from Procyon (P), to Rigel, and continued westward, it will 

 conduct the eye to the star (second magnitude) D, in the constellation Draco, 

 known in astronomy as y Draconis. This star is celebrated in astronomy as 

 that by observing which Dr. Bradley discovered the aberration of light. 



The midnight sky, in the months of March and April exhibits the zodiacal 

 constellations of Leo and Vergo, the constellation of Bootes and Coma 

 Berenices. These constellations contain three of the most splendid stars in 

 the firmament: Regulus in Leo, Spica in Vergo, and Arcturus in Bootes. 



Regulus is seen at midnight on the meridian, on the 20th February. In 

 March it passes the meridian between nine and eleven, and in April between 

 seven and nine. The point where it crosses the meridian at New York, and 

 other places in the same parallel, is about 30° south of the zenith. At places 

 south of New York it w T ill be nearer to, and north of New York more distant 

 from the zenith. 



Spica is seen at midnight on the meridian on the 10th April. In March it 

 passes the meridian between midnight and two in the morning, and in the end 



