I learned late on Friday that Gerry Neugebauer (Caltech) has died. Gerry was one of the most important scientists in my research life, and in my personal life. He co-advised my PhD thesis (with also Roger Blandford and Judy Cohen); we spent many nights together at the Keck and Palomar Observatories, and many lunches together with Tom Soifer and Keith Matthews at the Athenaeum (the Caltech faculty club).
In my potted history (apologies in advance for errors), Gerry was one of the first people (with Bob Leighton) to point an infrared telescope at the sky; he found far more sources bright in the infrared than anyone seriously expected. This started infrared astronomy. In time, he became the PI of the NASA IRAS mission, which has been one of the highest-impact (and incredibly high in impact-per-dollar) astronomical missions in NASA history. The IRAS data are still the primary basis for many important results and tools in astronomy, including galaxy clustering, infrared background, ultra-luminous galaxies, young stars, and the dust maps.
To a new graduate student at Caltech, Gerry was intimidating: He was gruff, opinionated, and never wrong (as far as I could tell). But if you broke through that very thin veneer of scary, he was the most loving, caring, thoughtful advisor a student could want. He patiently taught me why I should love (not hate) magnitudes and relative measurements. He showed me how a telescope worked by having me observe at Palomar at his side. He showed me how to test our imaging-data uncertainties, both theoretically and observationally, to make sure we weren't making mistakes. (He taught me to call them "uncertainties" not "errors"!) He helped me develop observing strategies and data-analysis strategies that minimize the effects of detector "memory" and non-linearities. He enjoyed data analysis so much, on one of our projects he insisted that he do the data analysis, so long as I (the graduate student) would be willing to write the paper! Uncharacteristically for then or now, he could run his group so efficiently that many of his students designed, built, and operated an astronomical instrument, from soup to nuts, in a few years of PhD! He had strong opinions about how to run a scientific project, how to write up the results, and even about how to typeset numbers. I obey these positions strictly now in all my projects.
Reading this back, it doesn't capture what I really want to say, which is that Gerry spent a huge fraction of his immense intellectual capability on students, postdocs, and others new to science. He cared immensely about mentoring. From working with Gerry I realized that if you want to propagate great ideas into astronomy, you do it not just by writing papers and giving seminars: You do it by mentoring well new generations of scientists who will, in turn, pass it on in their own work and their own students. Many of the world's best infrared astronomers are directly or indirectly a product of Gerry's wonderful mentoring. I was immensely privileged to get some of that!
[I am also the author of Gerry's only erratum ever in the scientific literature. Gerry was a bit scary the day we figured out that error!]