A newly developed UHF radiotelescope for interplanetary scintillation observations: Solar wind imaging facility

A large-aperture radiotelescope called the Solar Wind Imaging Facility (SWIFT) has been developed at the Toyokawa Observatory of the Solar-Terrestrial Environment Laboratory (STEL), Nagoya University. The SWIFT is dedicated to interplanetary scintillation (IPS) observations of the solar wind at 327 MHz, the same frequency as that of the existing STEL IPS system. The aim of this instrument is to improve the spatial and temporal resolutions of tomographic reconstructions from STEL IPS observations by increasing the number of usable lines of sight within a given time period. The SWIFT consists of a pair of asymmetric cylindrical parabolic reflector antennas with an aperture size of 108 m (N-S) by 19 m (E-W), and a 192-element phased array receiver system which forms a single beam steerable between 60°S and 30°N with respect to the zenith. Since the antenna beam is fixed in the local meridian, IPS observations are taken around the time of meridian transit for each source. The performance of the SWIFT has been tested using preliminary observations for strong discrete sources and diffuse galactic background.