Here is another ad that features Palomar Observatory. This one, from Corning, was run in the 1948 Caltech yearbook, The Big T.
Click to embiggen and you'll be able to read the text of the ad. The photo shows the honeycombed back side of the 200-inch disc. Standing with it is Dr. George V. McCauley (left) and Dr. J. C. Hostetter. Dr. McCauley directed the project of the casting the huge Pyrex disc.
The ad includes some interesting copy with lines like "the giant telescope atop Mt. Palomar, so powerful that the canals of Mars, if there are any, will for the first time be photographed."
Of course in 1948 just about every astronomer was already convinced that the "canals of Mars" were nothing more than an optical illusion. Curiously enough the Chief of Aviation and Optical Division of the Corning Glass Works, Dr. O. A. Gage gave a radio address in April 1936 (about twelve years before this ad came out) on the 200-inch mirror. In the address he said that there will be "no inroads on the inhabitants of Mars" - meaning no one was going to see any canals. Too bad the person who wrote the ad didn't check with Dr. Gage. His speech was printed in the Journal of the Royal Astronomical Society of Canada and contains some interesting stuff. You can see it here.
Oh, and 6,000,000,000,000,000,000,000 miles is a little over a billion light years. With modern digital detectors astronomers using the 200-inch telescope can see at least eleven times further than that.