Cygnus (sig´-nus)—the Swan, Or The Northern Cross.

Location.—Deneb, the brightest star in Cygnus, is at the top of the cross, and a little over 20° east of Vega. It forms a triangle with Vega and Altair in Aquila—Altair being at the apex, about 35° from Deneb and Vega.

β Cygni is at the base of the cross, and a line drawn from Vega to Altair nearly touches it. It is a beautiful colored double for a small telescope.

Note "61," one of the nearest stars to us. It was

the first star whose distance was measured (by Bessel in 1838). It is a double star and 10.4 light years distant.

The cross is nearly perfect and easily traced out. It lies almost wholly in the Milky Way.

Note "The Coal Sack," one of the dark gap in the Milky Way.

Cygnus contains an unusual number of deeply colored stars and variable stars.

ο Cygni has a sixth-magnitude companion, and γ is in the midst of a beautiful stream of faint stars.

This region is perhaps richer than any similar extent in the heavens. An opera-glass will reveal many of its beauties.

Herschel counted 331,000 stars in an area of only 5° in Cygnus.