I A Galaxy Revealed Among The Great Astronomical Mysteries Of The 1800s Were The Spiral Nebulae Which Appeared In Teles 1 (241.99 KiB) Viewed 12 times
I A Galaxy Revealed Among the great astronomical mysteries of the 1800s were the spiral nebulae, which appeared in telescopes as swirling cloudlike forms, but whose nature was unknown. Four different renderings of one such spiral nebula, designated M51, are shown in Figure 15-5. Figure 15-5A is a drawing from 1845 by William Parsons, the Earl of Rosse, who viewed M51 through what was then the world's largest telescope and sketched what he saw. Figure 15-5B is a picture from 1889 by English amateur astronomer Isaac Roberts, and is perhaps the first-ever photograph of M51. Figure 15-5C is a 1950 photograph that was taken through the largest-in-the-world telescope of that era, the 200-inch Hale reflector on Mt. Palomar in California. Figure 15-5D was obtained with the Hubble Space Telescope in 2005. Today we know that spiral nebulae like M51 are actually spiral galaxies, vast star systems like our own Milky Way galaxy. 13. Compare the four pictures of M51. Describe similarities and differences. 14. What factors might have led to the noticeable improvements in these images over time?