First light Book

The 200-inch Hale Telescope at the Palomar Observatory in California was built in the 1930s and the 1940s and started operating in 1948. By the 1980s parts of it had become ancient; the companies that manufactured them had long since gone out of business. Imagine a programmer working with 50-year-old legacy code, except it isn't code; it's physical. A few slight deformations of the mirror were corrected with springs from fisherman's scales; decades later an engineer saw the springs, wondered what they were doing in the telescope, and removed them: this was a bad idea! The person who actually ran the telescope was a Mexican American farmer's son, a former barber who got himself hired as a menial laborer and rose to become the senior night assistant; he wouldn't let Ph.D.s do things that could damage the machine. By the late 1980s, the light of the telescope was concentrated and fed into a camera with 4 800 by 800 pixel CCDs, which was the state of the art at the time. A third of the device consisted of "surplus parts and rehabilitated garbage" utilized by tinkerer astronomers. Originally the movement of the telescope was controlled by analog mechanical computers; by the 1980s electronic digital computers had taken over, but the old machines were kept oiled and ready in case the newfangled computers crashed.

The astronomers profiled in the book used the gigantic telescope to search for quasars. In the early 1960s astronomers found radio-emitting stars with spectra that made no sense; one astronomer thought that the spectral lines of one such star were those of curium, neptunium and plutonium. Another realized that something redshifted the bejesus out of the spectral lines of ordinary hydrogen. If these things are moving away from us as quickly as the redshift indicates, and are as far from us as Hubble's Law suggests, they must be billions of light-years away, and trillions of times brighter than the Sun. These are no stars. Thus was the study of quasars born. By the 1980s scientists arrived at a consensus that quasars are supermassive black holes that swallow many solar masses' worth of matter each year, converting a significant percentage of this mass to energy and radiating it away. As quasars are the brightest permanently shining objects in the Universe, they are the most distant things we can see and therefore the oldest: the light that arrives at our telescopes was emitted billions of years ago. They bring us closer to the first light in the Universe.

There is also a chapter on a husband-and-wife team of astronomers who were looking for comets and asteroids using a smaller telescope, but it isn't as interesting.