By pointing your camera toward that part of the sky and during that time of the year when there are showers of meteors, and opening the shutter of your lens, you stand a chance, though it is not a very fat one, of catching one of these wily shooting stars on your plate, and if you do succeed--well, you will have a picture that is a curiosity. You can photograph the Sun with an ordinary camera and make his disk as large as you want to, but you will get nothing more on your plate than a white spot. The Moon can likewise be photographed, but if you focus it sharp on the plate it will not be much larger than a mere point of light, and if you get a disk large enough to see there will only be a small white spot on your finished print. To make good photographs of the Sun, Moon and planets, a big telescope driven by clockwork to offset the turning of the Earth is needed. Such a telescope is called an _equatorial telescope_, and when it is set so that an object in the sky is in the field of view, it will remain right there as long as you want it, and when you make a photograph of the object it will be as sharp and as clear as though both it and the Earth were standing perfectly still. If you think enough of the stars to try to photograph them with your little camera, I should say there is a very good chance of your being able to photograph them sometime through an equatorial telescope _for all things come to the boy who wants them hard enough_. =What the Stars Are Made of.=--To know what the stars are made of is to know more about them than men knew of the Earth a few hundred years ago. But just think of looking at a star like Aldebaran, which is so far away that it takes 45 years for its light to reach the Earth--light travels eleven million miles a minute--and then saying it is made of iron, and mercury and hydrogen and sodium and half a dozen other substances! Now you ask, “How is it done?” And I’ll say with a _glass prism_, and then we’ll have made a flying start. Now a glass prism is a three-sided piece of glass--the ends don’t count--as shown in Fig. 144, and it is just as wonderful in its way as a lens is wonderful in its way. If you will hold a prism to your eye and look at the flame of a candle through it, you will see the flame in all the brilliant colors of the rainbow, and these bright colors form what is called a _spectrum_. Now make another experiment; cover a window, on which the Sun shines, with a sheet of cardboard, in the middle of which you have cut a horizontal slit with a sharp knife, about 1 inch long and ¹/₂₅ inch wide. Make the room perfectly dark except for the light which comes in through the slit in the cardboard, and set a prism in front of the slit, as shown in Fig. 145. The beam of sunlight which passes through the prism will be split up, or _decomposed_, as it is called, into the seven colors of the rainbow, but the colors will be much brighter.