Murchison Widefield Array
The goal of the Murchison Widefield Array (MWA) is to develop powerful new capabilities for radio astronomy and heliospheric science at frequencies from 80 to 300 MHz, optimized for extremely wide fields of view and unprecedented sensitivity at those frequencies. The MWA has specific scientific goals and is underway as an international project led by the MIT Haystack Observatory with strong collaboration from a number of international and Australian universities and research institutions (including Curtin University).
The most common configuration of radio telescopes is the typical parabolic dish with a detector located at its focal point. Most of these telescopes have the ability to move the beam by either adjusting the orientation of the dish itself or even moving the detector to a different point above the dish. This however can cause problems as strong winds can perturb the dish and destroy the integrity of data. A major advantage of the MWA is the fact that it has no moving parts. Rather than an array of dishes, this instrument will be a configuration of "tiles" each consisting of 16 dual-polarization dipole antennas.
Each tile consists of a large aluminium frame with a mesh ground plane. The dipoles sit on top of the ground plane by sliding through tubes built into the mesh, allowing a stable stronghold. Photographs of a dipole (left) and a tile under construction (right) can be seen below, showing the 16 dipoles on top of the ground plane.
The MWA will consist of 8000 dual-polarization dipole antennas optimized for the 80-300 MHz frequency range arranged as 512 "tiles", with 16 dipole antennas per tile in a 4x4 array. When fully functional the MWA will be able to offer radio astronomers with the following unique features:
- Reliability, as the design contains no moving parts
- Multi-beaming capability with higher resolution than existing low frequency telescopes
- High angular resolution due to spacing of arrays
- Advances in communication technology allows for terabit/sec (1,000 gigabit/sec) transfer speeds
- Lessened Radio Frequency Interference
- Ability to correct for ionospheric distortion of signals using GPS calibration
For more information see www.mwatelescope.org