ASTRONOMY WITH AN OPERA-GLASS. 749 



then comprehend that there is more than one sense in whieh to under- 

 stand the Scriptural declaration that " one star differeth from another 

 in glory." Turn next to the star in the map of Leo marked Zeta (£). 

 If your glass is a pretty large and good one, and your eye keen, you 

 will easily see three minute companion stars keeping company with 

 Zeta, two on the southeast, and one, much closer, toward the north. 

 The nearest of the two on the south is faint, being only between the 

 eighth and ninth magnitude, and will probably severely test your 

 powers of vision. Next look at Epsilon (c), and you will find near it 

 two seventh magnitude companions, making a beautiful little triangle. 



Away at the eastern end of the constellation, in the tail of the im- 

 aginary Lion, upon whose breast shines Regulus, is the star Beta (/?) 

 Leonis, also called Denebola. It is almost as bright as its leader, 

 Regulus, and you will probably be able to catch a tinge of blue in its 

 rays. South of Denebola, at a distance of nineteen minutes of arc, or 

 somewhat more than half the apparent diameter of the moon, you will 

 see a little star of the sixth magnitude, which is one of the several 

 " companions " for which Denebola is celebrated. There is another 

 star of the eighth magnitude in the same direction from Denebola, but 

 at a distance of less than five minutes, and this you may be able to 

 glimpse with a powerful field-glass, under favorable conditions. I have 

 seen it well with a field-glass of l # 6-inch aperture, and a magnifying 

 power of six times. 



When looking for a faint and difficult object, the plan pursued by 

 telescopists is to avert the eyes from the precise point upon which the 

 attention is fixed, in order to bring a more sensitive part of the retina 

 into play than that usually employed. Look toward the edge of the 

 field of view, while the object you are seeking is in the center, and 

 then, if it can be seen at all with your glass, you will catch sight of it, 

 as it were, out of the corner of your eye. The effect of seeing a faint 

 star in this way, in the neighborhood of a large one, whose rays hide 

 it from direct vision, is sometimes very amusing. The little star seems 

 to pop out into view as through a curtain, perfectly distinct, though 

 as immeasurably minute as the point of a needle. But the instant you 

 direct your eyes straight at it, presto ! it is gone. And so it will 

 dodge in and out of sight as often as you turn your eyes. 



If you will sweep carefully over the whole extent of Leo, whose 

 chief stars are marked with their Greek-letter names on our little map, 

 you will be impressed with the power of your glass to bring into sight 

 many faint stars in regions that seem barren to the naked eye. An 

 opera-glass of 1*5 aperture will show ten times as many stars as the 

 naked eye can see. 



Looking now westwardly from the Sickle of Leo, at a distance about 

 equal to twice the length of the Sickle, your eye will be caught by a 

 small silvery spot in the sky lying nearly between two rather faint 

 stars. This is the famous Prrcsepe, or Manger, in the center of the 



