Fig. 290.
Fig. 290 shows the transit of one of the satellites, and of its shadow, across the disk of the planet.
THE RINGS OF SATURN.
270. General Appearance of the Rings.—Saturn is surrounded by a thin flat ring lying in the plane of its equator. This ring is probably less than a hundred miles thick. The part of it nearest Saturn reflects little sunlight to us; so that it has a dusky appearance, and is not easily seen, although it is not quite so dark as the sky seen between it and the planet. The outer edge of this dusky portion of the ring is at a distance from Saturn of between two and three times the earth's diameter. Outside of this dusky part of the ring is a much brighter portion, and outside of this another, which is somewhat fainter, but still so much brighter than the dusky part as to be easily seen. The width of the brighter parts of the ring is over three times the earth's diameter. To distinguish the parts, the outer one is called ring A, the middle one ring B, and the dusky one ring C. Between A and B is an apparently open space, nearly two thousand miles wide, which looks like a black line on the ring. Other divisions in the ring have been noticed at times; but this is the only one always seen with good telescopes at times when either side of the ring is in view from the earth. The general telescopic appearance of the ring is shown in Fig. 291.
Fig. 291.
Fig. 292.
Fig. 292 shows the divisions of the rings as they were seen by Bond.