She had some horses (Part I)

October 4, 2013


I traveled to Denver for the 45th Division for Planetary Sciences conference in October, conveniently located three hours east of a dear friend of my mother. I drove west from the airport as the sun set and the haze around Denver gathered, darkening from a dusty rose to grey to black.  I went over two mountain passes over 10,000 feet tall, feeling no ill effects as I adjusted to the altitude.  Around the tunnels of Glenwood Canyon it began to rain, far better than snow for driving, but still exciting as the Jeep hydroplaned and lost traction on the highway.  I continued onward and wound up in the tiny town of Silt, 97 miles from the Utah border with Colorado.

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How planetary radar works at Arecibo Observatory

We know Arecibo Observatory for its 305-meter (1000-foot) diameter telescope and its appearances in Goldeneye and Contact.  Aside from battling Bond villains and driving red diesel Jeeps around the telescope (grousing at the site director about the funding status of projects is optional), several hundred hours a year of telescope time at Arecibo go toward radar studies of asteroids.  Tasked to “find asteroids before they find us”, a group of us four planetary radar astronomers at Arecibo (as well as collaborators and colleagues at institutions outside of Puerto Rico) observes asteroids for NASA’s Near-Earth Object Observation program. We study the orbits and surface properties of our rowdy neighbors, near-Earth asteroids.

William E. Gordon telescopeHow do we transmit and receive radio waves using the klystrons and radio receivers at the observatory, and how do we turn these into images of asteroids?  Read more on my guest post at the Planetary Society on how planetary radar at Arecibo Observatory works.

Scoping out the rowdy neighbors and baking Apophis cake

It’s been a pretty exciting week to be an asteroid researcher: you’d think the sky was falling!  Really, it was just a confluence of some rowdy neighbors checking in on earth asking, “How’s that space program coming?”  An ordinary chondrite meteorite exploded over Russia, and later that day a 150-foot-wide piece of spacerock skimmed 17,000 miles above the earth, just ducking inside the orbits of geostationary satellites.
We had nothing to do with either: the Russia bolide was detected maybe seconds beforehand by some satellites; 2012 DA14 was too low in our sky for Arecibo to observe.

The media guy here is still getting calls, almost a week later.  Univision came by, Dish Network wanted to interview someone…
Inline image 1 What are we doing in the midst of all this?  Regularly scheduled observations of asteroid (99942) Apophis, everyone’s favorite potentially hazardous asteroid that we’ve known about for almost nine years now.  None of these recently discovered raucous interlopers for us this week, pshaw.  Even so, the events of last week underscore the importance of “finding them before they find us” and commercial solutions to asteroid problems.
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Sailing on the seas of Titan

It’s past 3 am and we’re observing asteroids with the Arecibo planetary radar system. In the lulls between experiments, Twitter conversations covered everything from the Russian bolide explosion, 2012 DA14, Toutatis, rain on Titan, and some jokes about sailing on Saturn’s largest moon. The sky is falling, what else will you talk about?

Who would run the Titan sailing expedition?  I suggested myself and nominated Sarah as admiral; an aeronomer offered to be railmeat.  Cracks about how we’d all be “squidbate” went back and forth.  Brian christened our ship “The Calamari”.  Alex designed a mission badge.

Before I knew it, Justin “@UrbanAstroNYC” Starr had turned the whole conversation into a meme.

From @UrbanAstroNYC, “Sondy and friends go sailing on Titan”, with apologizes to Charles Schultz

My grandfather Bill Littlejohn used to animate Peanuts; he would have been 99 this year.  An animator, union organizer, test pilot, and airplane designer, his long and varied career reminds me that it’s okay that mine is taking a variety of twists and turns through technical and creative pursuits.  Bill grew up in a sailing family, and a few of his hand-illustrated birthday cards that he’d mail or fax every year involved sailboats and depictions of me with short brown hair.

Thank you, Grandpa, for all you created and gave; you’re living on as we continue to explore the cosmos.

Guiding out the waves: engineering planetary radar

I spent last week observing of asteroids from the telescope: our first night was just another 8-4 workday night, where we looked at space rocks in our neighborhood and out beyond Mars for eight hours.

Arriving at the control room, I sat down with my binder full of… notes on how to observe at Arecibo, which hadn’t made much sense.  At any optical observatory you enter your coördinates into a computer and take an image.  After verifying that you pointed the telescope correctly, you then tell the telescope system to take data for the rest of the night, occasionally adjusting pointing or focus.

Hector está llamado por telefono

At Arecibo, you’re pointed in the right direction.  Alignment with the William E. Gordon Telescope is not an issue.  Even with the 305-meter dish, you’re good to a few millimeters.

Position of the platform, receiver, transmitter

Getting the signal out of the receiver and properly into the computer is the hard part of observing.  Instead of a few shiny silvered mirrors and a charge coupled device digitizing and sending your photons to a screen, here a maze of waveguides, cables, and wires brings signals from the matte metal dish, after being ushered into the receivers, along a path 1,600′ long to the control room.  Where computer monitors would display starfields at an optical observatory, wavy lines danced across oscilloscopes at Arecibo.  It felt like junior year electronics laboratory again in the physics department, so different from most of the things we were doing in astronomy, and not just because of cgs/MKS units arguments.

Ellen had considered walking me through cabling the week before our six-night-long marathon observing run, but ultimately decided that it wouldn’t make sense out of context.  Wait for the actual observing run to understand the cabling.


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A week at Arecibo Observatory


A little over a week ago I arrived at the largest single-dish radio telescope in the world.  My boss picked me up at the airport and drove me up into the hills of Puerto Rico’s karst country where I caught my first glimpse of the support towers of Arecibo Observatory, peeking out over the wooded hills.

8 o'clock tower

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National Optical Astronomy Observatory of Japan

May 22, 2012


Just a few kilometers down the road from JAXA where I’d spent the summer of 2011 was 天文台通り, “heaven language hill avenue”.  By some combination of my lack of kanji comprehension and the supreme focus of my colleagues, no one put one and one together and so during my first seven weeks in Japan I managed to be unaware of the proximity of the National Astronomy Observatory of Japan.  I fortunately sat next to Ito-san at the ACM banquet, and he offered to give me a tour of the facilities.  I went back to see my old lab at JAXA, talked about the high quality of rice from Niigata, and was picked up by Ito-san in the midst of a rainstorm to visit NAOJ’s campus.

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