Marking the PAPER Trail

So last week I finally got out to Green Bank, West Virginia, to do some field work on our array, PAPER, or the Precision Array to Probe the Epoch of Reionization. It’s quite nice to run around outside and work on something physical to jumpstart your brain after being zombied-out in front of your computer. *sigh* Okay, also, I’ve been spending a lot of time developing assignments (loosely based on PAPER) for a radio instrumentation class, and needed to get back into actual research!

PAPER is an interferometer that is working in the frequency regime around 150 MHz. (Pay attention to an upcoming 365 Days of Astronomy podcast to hear all about the science!) We have a prototype sixteen antenna array at the NRAO’s site in Green Bank, in the Radio Quiet Zone. We have this great little field called “Galford Meadow” with a small equipment hut in the center and the antennas on a circle around the hut.


The Galford Meadow from Google Maps. You can see the hut, two tiny antennas, and the road. Okay, by road, I mean tire tracks.

I have proposed to add three outrigger antennas at greater distances from the hut, thus making longer baselines for better spatial resolution. Hopefully, this will give us an idea of the bubble, bubble, toil, and trouble that the ionosphere will cause for our imaging!

For this very first step, my friend and co-worker and I scoped out the farthest corners of the field and placed markers. That is what I snapped a picture of and posted a few days ago.


Looking back at two more antennas and the hut, from a pink-marked stake. The hut is almost 900ft away.

We then used a theodolite to survey the positions of the stake and mark appromiately 100-ft steps back towards the circle. This was really cool, since that means I got to learn how to use surveying equipment! It helps to know quite well where the antennas are in order to then calibrate the data. Also, my dear friend has very well calibrated steps and could walk almost exactly 100-ft just by counting paces. She was frequently within a fraction of a foot! That always helps.

We also explored the outer edges of the field, which seems to be bordered on all sides by a small metal fence from long ago. Hopefully, the metal won’t disturb our ability to take and analyze data too much. There seems to be a clearing in the northeast corner which can hold even longer baseline outriggers, as long as the wires can safely cross a small creek.


Frozen creek!

While we did this, two more of our friends and co-workers (we’re a close-knit lab) were out building new groundscreens for antennas that will be shipped to Western Australia. These just look cool when all assembled around our shipping container.


Field of telescopes, with the GBT feedarm in the background.

And, we got a visit from a girls high school group that was visiting on site! Sue Anne, Green Bank’s fabulous outreach and communications officer, noticed that we Charlottsville ladies (our lab is also mostly female!) were on site and asked if we’d be able to show the girls what we do. Of course we would! They seemed pretty interested in what we showed them, and they had a lot of good questions about our college experiences and how we got into science. So I was unintentionally doing some She is an Astronomer outreach. Cool.

Hope you enjoyed this little peek into the world of PAPER!


Next to 85-2, we are small but mighty.

3 comments for “Marking the PAPER Trail

  1. WoodEngineer
    March 12, 2009 at 19:38

    That sounds like a really interesting project. However a lab full of females, now that I like the sound of!! We don’t have any!!

  2. Richard Drumm The Astronomy Bum
    March 15, 2009 at 00:50

    Now I see where PAPER is! I thought (for some unknown reason) it was opposite the 40′ antenna! I stand corrected! This is a much better field for your array. Keep us apprised of your progress!
    Richard Drumm The Astronomy Bum

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