Not far from [xi] is [pi] Bootis, represented in Plate 5 as a somewhat closer double, but in reality—­now at any rate—­a slightly wider pair, since the distance between the components of [xi] has greatly diminished of late.  Both the components of [pi] are white, and their magnitudes are 3-1/2 and 6.

We shall next turn to an exceedingly beautiful and delicate object, the double star [epsilon] Bootis, known also as Mirac and, on account of its extreme beauty, called Pulcherrima by Admiral Smyth.  The components of this beautiful double are of the third and seventh magnitude, the primary orange, the secondary sea-green.  The distance separating the components is about 3 seconds, perhaps more; it appears to have been slowly increasing during the past ten or twelve years.  Smyth assigns to this system a period of revolution of 980 years, but there can be little doubt that the true period is largely in excess of this estimate.  Observers in southern latitudes consider that the colours of the components are yellow and blue, not orange and green as most of our northern observers have estimated them.

A little beyond the lower left-hand corner of the map is the star [delta] Serpentis, in the position shown in the Frontispiece, Map 3.  This is the star which at the hour and season depicted in Map 2 formed the uppermost of a vertical row of stars, which has now assumed an almost horizontal position.  The components of [delta] Serpentis are about 3-1/2 seconds apart, their magnitudes 3 and 5, both white.

The stars [theta]^{1} and [theta]^{2} Serpentis form a wide double, the distance between the components being 21-1/2 seconds.  They are nearly equal in magnitude, the primary being 4-1/2, the secondary 5.  Both are yellow, the primary being of a paler yellow colour than the smaller star.  But the observer may not know where to look for [theta] Serpentis, since it falls in a part of the constellation quite separated from that part in which [delta] Serpentis lies.  In fact [theta] lies on the extreme easterly verge of the eastern half of the constellation.  It is to be looked for at about the same elevation as the brilliant Altair, and (as to azimuth) about midway between Altair and the south.

The stars [alpha]^{1} and [alpha]^{2} Librae form a wide double, perhaps just separable by the naked eye in very favourable weather.  The larger component is of the third, the smaller of the sixth magnitude, the former yellow the latter light grey.

The star [beta] Librae is a beautiful light-green star to the naked eye; in the telescope a wide double, pale emerald and light blue.

In Scorpio there are several very beautiful objects:—­