Yesterday at dinner, I sat with two scientists from Oxford, who were at Palomar working on their instrument, SWIFT. When they mentioned that SWIFT uses Integral imagery, I immediately started thinking about x-rays (Swift and Integral are two x-ray telescopes), but the naming similarities were just a coincidence. SWIFT is an instrument created specifically for the Hale 200-inch telescope. There are many different types of instruments, each for a different purpose. Installing an instrument onto the telescope alters the results of the observation. For example, one instrument that had been used in the past is PHARO, which is an adaptive optics instrument. (However, the two scientists told me that adaptive optics is no longer being used at the Hale 200 inch! This was very surprising…)
What does SWIFT do? Best I can understand it, SWIFT is an integral field spectrograph. This means that it records not only the location (in the sky) of an event, but it also records the spectra at this point. This is useful because for larger sources, you can see the differences in spectra from one spot to another (still part of the same source). This technique is used for extended sources; it is not necessary for point sources, where a single spectrum is sufficient. An integral field spectrograph uses a different configuration of slits than a classic long-slit spectrograph (which took observations for the same purpose, seeing spectra over area). In long-slit observations, an observation is made through a (as the name implies) long slit aperture, and then the light is split by a prism. An integral field spectrograph speeds up this process. The result of using an instrument such as SWIFT is that an astronomer can study extended or grouped sources.
While explaining their project to me, the two scientists also ended up explaining a lot of science – I learned a lot! For example, I never knew that Keck wasn’t a monolithic mirror (I didn’t know what monolithic meant, either – it means that the mirror was one solid piece). Instead, Keck is many smaller mirrors aligned into a plane. The Extremely Large Telescope, which is a British telescope not yet built, will be 40 meters in diameter (!!!!) but will similarly be composed of many smaller mirrors instead of one single monolithic mirror. Also, apparently the problem they are having with building the ELT is not that they do not have enough money, but that they “can’t spend it fast enough” – that is, they cannot find enough qualified people to hire! Manufacturing the mirrors is a long process, and apparently not very efficient… car companies are more efficient than the people who build the telescopes!
I was very surprised at the degree to which the SWIFT scientists were aware and even bitter at the difference between the astronomers and the people who build the instruments. They both (although considering themselves scientists) lamented the fact that scientists never respect the people who build the instruments. I never thought about it before, but without the people who build the instruments, the astronomers who take and analyze data could never do their science. All modern science hinges on the fact that someone in history decided it was worth it to build a telescope – visiting the Hale 200-inch and seeing its battleship-like construction made me aware that telescopes are not built in a day, and no astronomer is self-sufficient… behind every paper are thousands of people whose labors have made it possible!
You bring up a lot of really good points! I'm so glad you had that conversation. Take as many opportunities like that as you can. When I was an undergrad I was pretty shy about that, and I wish I had reached out more.
ReplyDeleteYour last paragraph really rings home. Humans have evolved with the instinct to create hierarchies - who do we respect most, who do we value most - which was probably very useful when we were bands of monkeys living in the wild, but can be a bit frustrating now. A lot of theorists and observers sort of unconsciously see experimental astrophysics / instrument development as less pure astronomy or less challenging (hah!) or less significant, but none of those are true. I feel like it should be possible to recognize the importance of everyone's contributions to the progress of astronomy (theory, observation, instrumentation, and the many people who do more than one category) without having to decide which one is the most important. It's sort of like wondering which is the most important, my left leg or my right leg?