HOW TO OBSERVE THE HEAVENS. 339 



of April and the beginning of May it passes the meridian between midnight 

 and nine o'clock. It crosses the meridian at New York at 50 south of the 

 zenith, and will therefore be seen to more advantage in places further south. 

 At Charleston it passes the meridian 43, and at New Orleans 40 south of 

 the zenith. 



ARCTURUS is upon the meridian at midnight on the 22d April. During the 

 month of May it passes the meridian between nine and eleven at night, and in 

 June between seven and nine. At New York it crosses the meridian 20 

 south of the zenith, at Charleston 13, and at New Orleans 10 south of it. 

 In all parts of America this star is therefore seen to great advantage. 



In the annexed diagram, fig. 6, the collocation of the princip-al stars in these 

 three constellations is exhibited. The star ARCTURUS is placed at A, with 

 the principal stars of the constellation BOOTES around it. All except Arcturus 

 are stars of the third magnitude, and it is worthy of note that they are all 

 double stars. 



The star Spica is at S ; the other chief stars of Virgo, y, n, S, and V, being 

 of the third magnitude. The star y is in fact two stars close together, one of 

 which (that to the west) being a double star. 



The star Regulus, which is a double star, is at R. In the constellation 

 of Leo are also two stars, /? and y, of the second magnitude. These three 

 principal stars form a right-angled triangle, the right angle of which is at y. 

 This last star, y, is a double star. The three other chief stars of this constel- 

 lation, v, 6, and S, form an isosceles or equal-sided triangle, the base of which 

 is the line joining and <* 



It will be also observed that Regulus, Spica, and Arcturus, form a right- 

 angled triangle, the right angle of which is at Spica. 



In the months of May, June, and July, the heavens, during the night, ex- 

 hibit the constellations LYRA, AQUILA, HERCULES, OPHIUCHUS, and the 

 zodiacal constellations SCORPIUS, SAGITTARIUS, and CAPRICORNUS. These in- 

 clude but three stars of the first magnitude ; the star , in the constellation of 

 LYRA, ATAIR in AQ.UILA, and ANTARES in SCORPIUS. 



Antares is on the meridian at midnight on the 27th May. During the 

 month of June it passes the meridian between ten o'clock and midnight. This 

 star, however, being about 26 south of the celestial equator, is not seen with 

 advantage in the northern hemisphere. At New York this star passes the 

 meridian at 66 from the zenith, and therefore never rises to a greater altitude 

 than 34. At New Orleans its meridional altitude is 44, and it may accord- 

 ingly at the proper season be seen there more advantageously. 



The star a Lyra passes nearly through the zenith of New York at midnight 

 on the 29th June, and during the months of July and August may be seen 

 during the night, crossing the meridian between eight o'clock and midnight. 

 It is a splendid star of the first magnitude, and having no other bright star in 

 its neighborhood, is at once recognised. This is a double star. This star 

 passes the meridian in all parts of the United States within less than ten de- 

 grees of the zenith. 



The star Atair, in the constellation Aquila, passes the meridian about one 

 hour later than Lyra, and at New York crosses it at the distance of 30 from 

 the zenith. This star has in its immediate neighborhood, forming part of the 

 same constellation, seven stars of the third magnitude. 



In the annexed diagram, fig. 7, L represents <* LYRA, and A ATAIR. A line 

 joining these two stars of the first magnitude passes through four of the third 

 magnitude, y Lyra and y, 0, and Aquila. The four stars >, *, , and , are of 

 the third magnitude, and also form part of the constellation Aquifa. The star 

 Atair is a double star. 



