Friday, April 25, 2014
So, it's a simple bit of bookkeeping to figure out that my average speed - for the entire month of May, 24/7 - will be about 28 miles per hour.
Thursday, January 5, 2012
|Lowell Observatory's Hall 42", located at|
Anderson Mesa near Flagstaff, AZ
|An aerial view of the NOI & Anderson Mesa|
|In the end, there's little difference between this and rocket science:|
it's all about the plumbing
Monday, February 2, 2009
The Kepler field of view,
straddling the Summer
Triangle (Altair, Vega, Deneb). On March 6th, at 3:48 UTC, a Delta II launch vehicle will rise off the ground at Cape Canaveral's pad 17B, riding a fountain of fire being belched from its RS-27A main engine and 6 GEM-40 solids strapped to its sides like oversized fireworks. Three additional GEM-40 solid rockets get an air start about 2 minutes into flight, and burns of the Delta K second stage and Star 48B third stage will loft the Kepler spacecraft into an orbit around the sun, drifting away from the Earth at slow rate over the following years. After the roaring earthquake-in-a-thunderstorm ride to that orbit, Kepler will settle into the deep interplanetary quiet - an ever waking, watchful sentinel, on the lookout.
During its long stare, Kepler will seek - and find - planets like Earth: the size of Earth, orbiting stars similar to our Sun, separated from their host stars at distances similar to the Earth-Sun system. Places where liquid water are thought to be likely, where life can flourish. Terra Nova.
Kepler will do so by looking with its large, unblinking eye, at a huge, heavenly (literally) host of stars - initially, about 200 thousand - taking a digital picture and measuring the brightness of each of those stars once every few minutes. The exact same field of stars, for 4 long years (and even longer if a mission extension comes to pass). If one of those stars happens to be Sun-like, if it happens to have an Earth-like planet, if that planet happens to be in a Earth-like orbit (about 93 million miles from its host star), if that orbit happens to pass between us and that star, and if Kepler is looking during the transit event, then a detection might occur. Stare long enough, the planet's orbit will swing it around for a second transit, establishing the duration of the orbit - and then later, a third: confirmation. A lot of if's - and the mission design attempt to solve that: look at a lot of stars, with a regular rate, for a very long time - four years or more, in fact. Each one of the "if's" I mentioned has a small likelihood of success associated with it, but if you beat enough targets, for long enough, against those small probabilities, one can still come up with non-zero discovery rates.
Assuming the rocket doesn't blow up on launch (yet another 'if' - but the Delta II's are about as resoundingly reliable as they come), and if the satellite functions properly, what is the expected haul of planets? This is difficult to say, actually - astronomers don't have much information on how common Earth-like planets are - this is a major motivation for the mission. But, if current models are true (they are, every blue moon), the expectation is that roughly 50 Earth-like objects will be found, in addition to a large number of bigger objects (such as Neptune-sized objects).
Currently there's a similar smaller scale mission, CoRoT, flown by the French space agency CNES, which in turn was predated by an even smaller scale mission, MOST, flown by the Canadian Space Agency. CoRoT just celebrated its 2nd year anniversary, and MOST has been orbiting since mid-2003. Both CoRoT and MOST can detect large-ish planets (giant gas bags like Neptune and Jupiter) - particularly if the host star is smaller than our sun - but Kepler's scope (roughly a factor of 10 larger than CoRoT) allowed it to be designed specficially for the goal of finding distinctly Earth-like planets. It's an exciting prospect - one more step on the Copernican Revolution started over 400 years ago, one that will not only expand the frontiers of our scientific knowledge, but one that will distinctly impact humanity's sense of its place in the universe.
Sunday, February 1, 2009
So I am, once again, at the Paranal Observatory, observing with the Very Large Telescope Interferometer (VLTI). VLTI uses multiple telescopes to synthesize a single, larger telescope - one of a size that is far beyond what is practical to build by itself. For example, we are able to configure our telescopes to act like a telescope more than 100-m in diameter - something that would be nice to have but is not economically feasible.
We are in the process of commissioning a new instrument for VLTI called PRIMA - I'll save you the pain of what the acronym means and cut to the practical impact of it: PRIMA allows us to observe two objects simultaneously. It effectively lets the VLTI behave like an interferometer, times two. This setup lets us do a couple of tricks - first, it will allow us to look at things fainter than we normally can, by using one of the two channels to lock up the optics on a bright star, while the second channel stares at something dim. Second, PRIMA will let us measure the angle between those two objects to an unprecedented level of accuracy, something south of 100 microarcseconds.
Pretty cool, huh? But here's the catch: VLTI is a rather complicated beast, and PRIMA makes it all that much worse. So, we shipped PRIMA out to the site last August, and we've been working to get it functioning ever since. It'd been expected that there would be an extended period of commissioning to shake out all the bugs (think of it as a test flight regime for a new aircraft), but some times the observing runs associated with commissioning can be a challenge when new & exciting optomechanical system do new & exciting - and unexpected - things. So at times we're left scratching our heads. ("Huh? The star separator did what?")
The moon and Venus in conjunction This particular observing run has been like that. We fix one thing and something else breaks or misbehaves. It's currently day 4 of 10 - and things overall are only getting better - but it's turning into a long haul. We'll be ready for the bus in a week! However, as we like to say (and first attributed to Albert Einstein), if we knew what we were doing, it wouldn't be research...
[nb. tip 'o the hat to The Blog Doctor for tips on image posting in Blogger.]
Wednesday, January 28, 2009
Working in the field of astronomy, there are many and wondrous things that one often encounters during the course of one's travels. In many cases, the sights are sufficiently novel as to leave one scrambling to place them in context in an inadequately rich cultural backdrop. This is, of course, ever-so-true for the images that astronomers pluck out of the sky each and every day.
Telescopes are often located at the very extremes of the earth (and beyond). These locations are generally selected for environments that are as benign as possible - but not from the point of view of their human operators: these considerations are purely driven by the needs of the machines. Locales that are very dry, cold, and high atop mountains figure prominently on the wish list for sites for observatories. These locations often have staggering vistas associated with them - stark landscapes that seem to have been ripped off the surface of the moon, rather than having anything to do with Mother Earth.
And finally, the telescopes themselves often defy convenient categorization, being objects of purpose-built wonderment that have lines that curve and swoop in unfamiliar ways. These machines are often reflections of their times (for example, the 100" Hooker telescope looks a lot like other large things of its era - battleships!) - the fingerprints of the technologies out of which they were born are all over them, even if they themselves look nothing like the more conventional applications of that technology. Think of what would have happened if Andy Warhol had been locked in a Dunkin' Donuts kitchen and told produce some art. It'd be something wacky & cool & unexpected, but you know it'd have a certain familiarity because it'd be deep fried and covered in powdered sugar, too.
Having recently come back to ESO's Paranal Observatory to use the VLTI, I sometimes reflect upon these things as I wander around outside on the observing deck. On the deck are the 4 outsized domes for the UTs (the cleverly named 'Unit Telescopes'), the VLTI building, and the 4 AT telescopes (the also cleverly named 'Auxiliary Telescopes'). The ATs are specifically designed to be used with the VLTI, and as such, rank high on my list of personally important astronomical glass. The ATs are interesting little telescopes1, designed to be compact and can even be driven around like futuristic street cars. The flat white finish could easily have been designed by Apple, like some outsized iPod (is it too late to trademark the term iTelescope?), but recently I have discovered an even closer cultural link for them.
It's something that nagged at me for some time - that "I've seen this before" feeling that I couldn't put my finger on. And then it hit me: the ATs could easily be mistaken for Marvin, the oppressively depressed robot from Douglas Adam's ever-so-delightful Hitchhikers Guide to the Galaxy (at least, the movie version). The resemblance is striking - so much so, it gives me pause: did any of the film's producers visit Paranal before filming? Where did that Marvin design come from, anyway? And using Alan Rickman's voice in the movie for Marvin - it's just like when Rickman was in Die Hard, and they blow up the place, which of course is what happened to Paranal in Quantum of Solace. Coincidence? I think not.
1"Little" being a relative term - at 1.8m (71") in size, they're small only next to the 8.2m UTs.
Friday, January 23, 2009
Wow, talk about an alarmist headline. But it's true! Why? There is a machine at ESO, a magic machine, one that single-handedly fuels the engine of astronomical discovery. I have often remarked that it is the single most important machine at the facility. What is it? Tucked away in the heart of the ESO cafeteria, sitting atop a shiny stainless steel countertop that has been devoted to it alone, like an altar, is the ESO espresso machine.
Its sheer size and glittering controls are sure to elicit a mouth-dropping expression of wonderment from the newcomer. ESO veterans know to make a beeline every morn immediately upon arrival at work for this cathedral of caffination and pay homage to its wonderous powers of brewing and steaming. Wizened oldtimers of the institute remark that its prodigious mind-enhancing output - estimated to be well in excess of 30,000 cups of black, liquid lightning a year - has single-handedly led to more discoveries than any comparable device in the modern world.
But alas, this morning, a mournful sign hung like a rude stoplight on the front of the machine. "Out of order," was its tale of woe. Progress today at ESO? Perhaps not. Perhaps the ephemeral mysteries of the universe will hide yet one more day behind the mists of uncertainty, with no minds coffee-sharpened like razors to cut away at the fog that hides discovery. But, "a technician has been called", the sign goes on to read - so there is hope for yet more insight will eventually come in seeking the secrets of the universe...
Thursday, January 22, 2009
Yes kids, here I am today, digging away in search of the next Rosetta Stone that will explain the latest round of interstellar mysteries, slogging it out with ... Microsoft Project?
Welcome to the era of Big Science. Actually, that era has been going on for quite some time - probably the best early example of the über-project is the Manhattan Project. For me, the engineering projects I've worked on have been small-ish teams - typically a dozen or so people - but even that requires careful choreography at times. That's where necessary evils such as MS Project rear their ugly heads.
For example, next week, I'll be going to Chile to ESO's Paranal observatory to work on the PRIMA Instrument. During that time, there will be about a dozen people, all tinkering around with different aspects of the same instrument. What's to keep one person's change not appearing as an effect that someone else thought they did? Choreography. More precisely, "careful management of project personnel and instrumention resources" - basically, making sure we're not stepping on each other's toes. This is MS Project comes in: I tell it who's going to be there, and what bits of laboratory are available, and then list all of the tasks that we'd like to do over the 10 days that we'll be there. Each task has people and bits of lab tied to it, and a preferred order in which it gets done relative to the other tasks. MS Project, being told that, makes sure the order is followed and that nobody is being bookkept to do 20 hours of work in a single day. (We like to keep it to more like, oh, 16 hours a day.) At least in theory this is what Project does - in practice I've found it to be an arbitrary and capricious beast, no amenable to taming.
Think of it as being the sole teacher in a schoolyard during recess when one shiny new slide has been installed - on a merry-go-round - next to a lake. You have a rusty old whistle that only works half the time, and you're trying to make sure that everyone get a turn, and that no kids bump their heads, shoot off the spinning slide into each other, or get wet. Ok, stupid analogy. But can you think of a better one?