Today progress on the Prescott HERA dish took the form of building the dish hub and rim.  The hub is where all the dish supports (25′ pvc pipes) meet. The hub is made using concentric “sonotube” concrete forms in which are embedded 3″ plastic pipes set in a radial pattern.  Its basically a giant tinker toy hub made of cement. At the same time we also put up the rest of the rim support poles with their fixtures to receive the dish supports.

HERA Prescott Photo Album

Our work team today.

When building any kind of instrument its really important for the people looking at the data to understand all the little things that go into building it and from an experimental perspective its key to be able to experiment with the hardware.  With the primary construction going on in South Africa this is a challenge. Travel to site is key, but sometimes you can’t beat having your own copy.

With support from ASU, the Bowman lab, Embry Riddle,  in collaboration with ERAU Professor Andri Gretarsson we are building a HERA dish at the Radio Observatory on the ERAU Prescott campus.

Today the survey was completed and the three primary telephone poles were installed!

HERA-Prescott poles. Ellie Gretarsson for scale.

Last week the ECHO team took the (relatively) short drive from Tempe up to Prescott, Arizona and Embry Riddle Aeronautical University to do some more testing at a new location.  The Embry-Riddle Physics department has put together a very nice campus observatory which is predominantly devoted to radio science, both astronomy and aerospace. Under the leadership of Professor Andri Gretarsson, they have set up a set of three MWA tiles with which they plan to observe pulsars, and antenna elements from LWA and from LOFAR. On this trip we got shown around the site, made a preliminary map of one MWA tile, and discussed plans in the works to build a HERA dish.

Part of the ECHO team poses with an LWA antenna and the ECHO drone on the May, 31 trip to Embry Prescott, AZ. Left to right: Lauren Turner, Jacob Burba, Prof. Andri Gretarsson (ERAU), and Dr. Daniel Jacobs (ASU)

Part of the ECHO team poses with an LWA antenna and the ECHO drone on the May, 31 trip to Embry Prescott, AZ. Left to right: Lauren Turner, Jacob Burba, Prof. Andri Gretarsson (ERAU), and Dr. Daniel Jacobs (ASU; ECHO PI)

We only had a few hours in the afternoon to map the tile, so we hurried through three sorties and hoped for the best.  Getting home and processing the data we were pleased to see the expected square sidelobe pattern (shown below). The errors are still a bit high due to a low sample count, so we’ll be heading back up as soon as we can to get more data.

The beam map from this run.

The beam map from this run. It came out surprisingly well for such a quick attempt at data collection.

Onward to 32!

This month we added another shipment of 16 antenna to bring PAPER to 32 antennae.  The arrangement of the antennae on the ground is very close to random, making geography tricky!  I spent a good amount of time out there with the GPS pole and pack, marking out locations of antennae.  We also deployed 4 extra antenna to do a polarization experiment, but ran out of time. Literally and figuratively. First we barely got things running before we had to leave and then the timing turned out to be off by an unknown amount. Still, another great field season!


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I’ve just returned from building the first 16 antenna section of PAPER in South Africa. The site is in the northern part of the country in the middle of the Karoo desert. With its brown sandy dirt and scrub brush the desert is much like middle New Mexico and felt just like home! Here is a photo gallery of the best pictures from the trip.
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We set up 16 antennae on a patch of land set aside by the South African Square Kilometer Array organization with our computers inside a radio-tight shipping container also kindly lent by the South Africans. Everyone was friendly and helpful. It was a very exciting trip. Within days we were able to set up 16 antenna and make our first image of the southern sky at radio wavelengths.