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.

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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Lick Observatory, Mount Hamilton

February 15, 2012

Another year, another telescope trained on another asteroid.  I spent the evening of February 15 at the summit of Mt. Hamilton near San Jose with the 40″ Nickel telescope pointed at (22) Kalliope and its moon Linus.  The asteroid slowly plodded across the camera frame as the hours ticked by from sunset until 1 am.  The weather was clear, if windy.  Most of the observing was supposed to be done remotely from a basement at UC Berkeley, but I had to be checked out first at the actual telescope before I could remotely observe, so away I drove to Mount Hamilton.

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