Primeval Structure Telescope
May, 2005With the frigid Tibetan Winter coming to an end, major construction at the PaST site in Ulastai, China is soon to resume. Currently, about twenty pods of 127 antennae each are assembled, about twelve of which are calibrated and collecting data. As the remaining pods are calibrated, work will continue on construction of more pods: it is expected that forty or more pods will be assembled, tested, and calibrated for data collection by the end of this Summer.
Meanwhile, a small prototype was placed at the South Pole to test the level of terrestrial radio noise in that area over the Antarctic Winter. Between the months of April and September, the South Pole receives virtually no Sunlight, reducing the reflectivity of the atmosphere. Therefore, cosmic radio waves pass more freely through the atmosphere. The prototype placed at the South Pole will allow us to compare this site to the site at Ulastai, China.
Expansion continues on the PaST array in Ulastai, China. All ready, about fifteen pods of 127 antennae each have be constructed at the site. Current plans for this phase of the expansion call for a total of twenty such pods. Please refer to our Images for more details.
Once this physical construction is done, the pods will be linked together via the on-site correlator computer which is currently also being expanded to accept and process such a larger amount of data. This process is managed by a team of five programmers based in Beijing.
The expansion of the PaST Prototype in Ulastai, China for this Fall has been completed. The telescope now consists of two pods of 127 antennae each. The entire structure has been deliberately kept a modular in design so that different materials can be tested. Please consult the Images page for pictures of the completed pods and various material tests.
While physical tests and modifications are made, we have begun collecting and processing data from the array. We hope to be able to generate even more detailed images of the radio bright sky in the near future. While we do not expect the array to be able to detect reionization at this stage of its development, this data will be critical for calibration of the telescope and the refinement of our data-processing techniques.
Progress continues on the upgrade of the PaST Prototype in Ulastai, China. This design calls for two pods of 127 antennae each. The basic structure of the antennae will remain unchanged but they will be laid out in a new pattern to optimize collection. Furthermore, fiberglass or metal poles will be used to raise the antennae off of the ground so as to prevent any possible interference with the ground. Construction is continuing and once completed, we will be able to perform tests on the system and collect data samples.
Meanwhile, progress continues on a prototype for Antarctica. Current plans call for the use of several antenna designs over several frequency ranges. Furthermore, rapid progress has been made on the design of a computer system to control the amplification and processing of signals as well as the collection and storage of data.
An expansion of the PaST Prototype in Ulastai, China is planned for later this month. The current prototype there contains a few dozen elements, but the expansion will contain approximately three-hundred elements distributed over two pods. Each pod will be comprised of various concentric, regular hexagons. The choice of hexagons was a natural one since they provide the densest possible packing of antennae. Using various power combiners and precisely cut lengths of coaxial cable, the antennae within each pod will be combined, and the summed signal will be sent sent into the correlator for processing and subsequent analysis. Based on our current expectations, this apparatus will be able to perform preliminary, statistical observations of the background radiation.
We have built a functioning prototype consisting of a few dozen antennae installed at Ulastai, Xin Jiang, China to test the design of the project. This system is already detecting radio-bright galaxies, seeing as far back in time as three-billion years (please refer to the paper "Forecast for Epoch-of-Reionization as Viewable by the PrimevAl Structure Telescope (PAST) by Pen et alii" and Prototype Images for more details). An expansion of this prototype to one-thousand antennae is planned for the Fall of 2004. We are planning to test the feasibility of the South Pole as a site for this type of astronomy. While Ulastai, China is rather isolated, the South Pole is more so. This is important since interference from broadcast stations, cellular telephone towers, and machinery can interfere with the function this type of telescope. Therefore, it is expected that a telescope at the South Pole would result in clearer data. Furthermore, during the long winter, the ionosphere above the South Pole becomes quiet and practically transparent. This may allow the South Pole to be used to observe lower frequencies: id est, to look further back in time. Within a year, we expect to be able to make a direct comparison between sites.