In the grip of the big telescope age

摘要

George Ellery Hale was a man of many dreams. One of his mostpersistent was to find the means to collect as much light as possible, but thereis another element in his designs for the modern astrophysical observatorythat has even greater significance, as it defines and distinguishes the practiceof astrophysics from that of classical astronomy. Here we examine factors thateither impeded or drove the acceptance of reflectors over refractors around theturn of the twentieth century at the outset of what may best be called the "Haleera." This commenced in the late nineteenth century, when the first large multi-focus photographic reflectors emerged during the reign of the great refractors.It lasted through to the onset of World War II when astronomical practicewas dominated by ten reflectors with mirrors between 60 and 100 in., and wasabout to add one more whose surface area would almost double that of all therest combined. We will touch upon how design choice reflected both scientificpriorities and technological limitations.