Notes from the Astronomy Underground: Unappreciated Topics in Astronomy Part III

August 29, 2008, 1:23 pm
Topics:
This content is not assigned to a topic
Content Cover Image

Black Holes. Gamma-ray bursts. The hunt for extrasolar planets. Cosmology and the grandest scales of the cosmos. These are the fields of astronomy with the glitter and sweeping majesty of The Big Picture; sexy fields so infested with the most impressive contemporary buzzwords that NSF funding will chase you down like a pack of rabid ferrets should you show the slightest desire to work in them. But what about the other fields and attendant scientists, the ones that prefer to linger in relative obscurity, the ones to whom you could imagine all the other astronomers awkwardly crooning Bette Midler’s Wind Beneath My Wings?

Well, don’t actually imagine that. Trust me, it gives you really weird nightmares.

Anyway, it’s in honor of these thankless men and women of science I present:

Unappreciated Topics in Astronomy Part III: Instrumentation

The Job Description

Well, I’ll be perfectly honest- this particular field is way beyond my expertise. In fact, I misspelled “Instrumentation” the first time I wrote it here (I guess it didn’t really have a silent q after all). Even worse, the last time I had any hands-on experience with components of the scientific method that weren’t ones and zeroes floating around the bloated innards of a Linux machine was the Electronics & Instrumentation class I took as a junior in college. And I’m not going to say it was a complete disaster, but the only useful thing I built the whole semester was a pretty sorry-looking and blatantly illegal beer quality tester.

That, and a few fires from slovenly, piecemeal circuits, actually. I was politely advised to pursue more promising career avenues after that. Something about making the lab smell like twisted metal and a southern Pennsylvania American Legion outpost at 3 in the morning.

Anyway, I’ll give you a quick run-down of what I know.

Over in optical/infrared (lR) land, instrumentalists are in charge of designing and building the reliable, amazingly efficient CCD cameras and spectrographs that allow the rest of us to unabashedly make all these amazing claims about the star formation properties of galaxies millions of light years away, abundances of elements, dust grains, and all sorts of crazy molecules in space. Even more incredible is that we’re just starting to get a feel for the compositions of extrasolar planetary atmospheres and can speculate a little less wildly about the prevalence of life in the universe.

And actually, all this is even harder than it sounds, especially for long wavelength observations where practically everything around you (including the atmosphere and the telescope itself) emits radiation in the wavelength range you want to observe. On top of that, detector response gets all screwy and nonlinear, with each individual pixel having its own time- and temperature-dependent properties.

Sure, you can strap your IR telescope onto a rocket and launch it into space like astronomers have done for Spitzer and Hubble, and will follow up for the upcoming James Webb Space Telescope. That one’s boasting a pretty impressive resume with the Near-IR Camera, Spectrograph, and Mid-Infrared Instrument. We’re talking a 4096 x 4096 pixel imager, a spectrograph with a malleable array of 64000 microshutters to select individual objects for study from a 3.4’ x 3.4’ field of view, and a composite camera/spectrograph that combines the best of both imaging and spectroscopic worlds.

That is a lot of intelligent-sounding specs. But personally, I’m still a bit uneasy about working with a telescope named “Jimmy,” of all things.

Let’s not forget that we need to cool down the whole telescope to eliminate that pesky thermal emission, too. Chilling a telescope to a few degrees above absolute zero, with the sun’s unmitigated radiation bearing down on it the whole time? This stuff sounds as hard as sitting through the last 20 minutes of the past week’s The Office finale. I still haven’t forgiven Ed Helms for what he did.

Ok, it’d be easier and more cost-efficient to keep your equipment on the planet, but for IR it’s best to get above that noisy water vapor in the atmosphere. The folks working on SOFIA seem to have come up with kind of a bizarre compromise- they put a whole telescope on a plane. Ignoring the logistics of getting the thing to track and focus while situated uncomfortably close to a jet engine, I’d still be worried about having to sit next to a colicky baby or that really gross sweaty guy that wheezes a lot during an observing run. Not to mention all the time lost by getting stuck at O’Hare and taxing the runway for days.

I’m also tempted to make a pithy Snakes on a Plane reference here, but I don’t think I’m allowed to swear like that in a public forum.

Over on the high energy side of the spectrum, one of my friends and fellow grad here at Penn State is working on an X-ray detector that will have a couple of advantages over the current generation of CCD-style detectors currently in use. As with optical CCDs, instrumentalists are always looking for ways to get the chip to “read out”- spit its data at the receiving computer- faster. They’re also trying to siphon off this information from different parts of the array at varying rates. All of this while still keeping the reliable resolution and low electronic noise the devices have now.

Why is this such a big deal? Reading out the chip can take up a lot of valuable time, especially if you’re a satellite that’s got a full schedule of observing ahead of you until your cryogens or power inevitably run out. And if you’re a person, well, then you get to stay on Earth and do fun things like go to the IHOP and eat pancakes. Of course, if I had my way, all these monumental technological advancements to solid state arrays would invariably include pancake-making as a fundamental design requirement. I’m really quite shocked that no one agrees with me on this. Come on. A state-of-the-art CCD chip that cooks you breakfast every day. In space. That would be awesome.

As with all fields of astronomy, Instrumentation would be nothing without the unnavigable myriad of oppressive federal bureaucracy making you beg like a dog for every penny you earn. Unlike the projects I’ve worked on, where you just need to justify telescope/satellite time and student manpower squandered on Minesweeper and YouTube, instrumentalists need some serious money and high-tech equipment to build their increasingly complex and sensitive detectors. I mean, as impressive as the Professor was on Gilligan’s Island, you really can’t fashion a CCD chip or spectrograph solely out of coconuts and palm leaves. Granted, MacGyver can, but I don’t think Richard Dean Anderson does that kind of stuff anymore.

In reality, “small” projects with an employ of a handful of personnel can take advantage of programs like SMEX that scrounge up the meager few millions needed for resources and salaries. It seems like a lot of money, but this is actually the low end of funding requests, for projects purchasing instruments for analysis that have already been made.

It gets complicated for the bigger projects. According to my sources, “a larger project pools together multiple organizations into a consortium who each give money and manpower.” Sounds like a diabolical amalgam of Terry Gilliam’s Brazil and every legitimate concern about heartless corporations raised by big haired pop bands of the 1980s, doesn’t it?

Yes, I’m listening to We Built this City by Starship right now. No… no, I’m not proud.

Why No One Likes It

I think it’s a fair assessment that a lot of astronomers don’t really care so much about how data are obtained, just as long as it gets done. I’m very guilty of that. As long as the data end up on my computer, I don’t care if they’re delivered by a team of highly trained experts or Ed McMahon flanked by a squad of parachuting circus bears.

Actually, I think I’d like the last option better. There’s something about skydiving bears and Star Search that’s just so inexplicably appealing.

The bottom line is that Instrumentation as a field is only transparent when something goes wrong. Remember what happened to the Hubble telescope? That whole mess about spherical aberration and fuzzy images and all that? Never mind that the technicians got the mirror ground perfectly to an accuracy of 1/800,000th of an inch, but everybody went all Tom-Cruise-is-a-Scientology-Spouting-Nutcase crazy when it didn’t work quite right. It’s almost like we all just forgot about the scientific method and replaced the “take replicable, precise measurements” part with “and then magic happens.” It’s kind of ironic, especially when we’re always up on our soap boxes about the unquestionable importance of science as civilization’s greatest intellectual movement.

So really, on a scale from “grad student” to “fluorescent light bulb,” instrumentalists fall somewhere in that depressing middle region in terms of public and academic appreciation. And to be clear, “grad student” is the low end of the scale, not the high end.

Who Does This Stuff?

It kind of seems like the underlying theme in this series of Articles on Parts of Astronomy People Should Respect or at Least Be Vaguely Aware Of is that working in such a publicly marginalized subfield requires an innate self-motivation that borders on the clinically insane. Now that may also be a consequence of my ever-unbiased and professional journalistic flair, but in this case it’s true. How deeply absorbed are instrumentalists in their work? Well, if you checked that SMEX website, you might notice that these guys are so busy that they haven’t updated their website since 1999.

Which is pretty cool, actually- it feels like you’ve opened up an esoteric internet time capsule or something. Almost makes you nostalgic for Y2K, unregulated music piracy, and a functioning economy.

But seriously, instrumentalists are a special breed with complimentary interests in science and the technological process that stimulates it. In practice, understanding both the engineering of astronomical detectors and the science they’re designed to do put this hybrid engineer/scientist species in an ideal position to build the best equipment possible. Which is good, since finagling a handful of photons out of a brutal cacaphony of atmospheric and thermal emission is not exactly trivial. Unsatisfied with blindly accepting the apparent magic of data acquisition, these valiant men and women are the true epitomes of the meticulous Scientist the rest of us only pretend to be.

So, instrumentalists of the world, if I ever see you at the bar, next round’s on me. Just… no fancy mixed drinks, please. I’m not made of money, here.

Glossary

Citation

Mullan, B. (2008). Notes from the Astronomy Underground: Unappreciated Topics in Astronomy Part III. Retrieved from http://www.cosmosportal.org/view/blog/133451

0 Comments

To add a comment, please Log In.