In this task, you're given a passage, further information available on a particular linked term from the statement, and a question. Your job is to generate the answer to the question by using the information provided. If there is no clear answer obtainable, output 'none'.
Q: Passage: Neugebauer was active in infrared astronomy, and played a leading role in infrared studies of the planets. In addition—and largely through his activities with the Infrared Astronomical Satellite (IRAS) and the Infrared Processing and Analysis Center (IPAC)—he led both ground- and space-based infrared studies of the stars, the Milky Way and other galaxies. Observations by him and his colleagues at Mount Wilson and Palomar observatories revealed thousands of infrared sources in the sky, and afforded the first infrared view of the galactic center. Together with Robert B. Leighton, he completed the Two-Micron Sky Survey, the first infrared survey of the sky, which cataloged more than 5,000 infrared sources. Together with Eric Becklin, he discovered the Becklin–Neugebauer Object, an intense source of infrared radiation in the Orion Nebula that is one of the brightest objects in the sky at wavelengths less than 10 micrometres.
 Link Information: Together with Eric Becklin, he discovered the Becklin–Neugebauer Object Question: Which colleague Neugebauer collaborated with at Mount Wilson Observatory is the oldest?
A: 
Answer:  Robert B. Leighton