original question: Which astronomical discovery technique is used for discoveries of [W. M. Keck Observatory]?
answer: doppler spectroscopy (radial velocity)
answer type: Astronomical Discovery Technique.
auxiliary information: The W. M. Keck Observatory is a two-telescope astronomical observatory at an elevation of 4,145 meters near the summit of Mauna Kea in the U.S. state of Hawaii. Both telescopes feature 10 m primary mirrors, currently among the largest astronomical telescopes in use. The combination of an excellent site, large optics and innovative instruments has created the two most scientifically productive telescopes on Earth.
What is the name of the astronomical discovery technique that is used for discoveries of [W. M. Keck Observatory]?