Experiments with a Three-Element Radio Interferometer in 12 GHz

• Published in: Journal of the Korean Astronomical Society, 57(1) Vol. 57; no. 1; pp. 25 - 33
• Main Authors: Jeongwhan Han, Sang-Eun Jung, Bangwon Lee, Inwoo Han, Biho Jang, Yong-Sun Park
• Format: Journal Article
• Language: English
• Published: 한국천문학회 01.12.2024
• Subjects: 천문학; instrumentation: interferometers— Sun: radio radiation— radio continuum: general
• ISSN: 1225-4614; 2288-890X
• DOI: 10.5303/JKAS.2024.57.1.25

In order to attract students to the radio universe, we have constructed a three-element radio interferometer in the National Youth Space Center, Goheung, Korea. It consists of three 1.8 m off-axis parabola antennas with driving systems, sideband separation receivers operating in 12 GHz, a narrow band digitizer, and correlation software. We have used as many commercial products as possible to reduce development costs. The maximum separation of 20 m gives an angular resolution of ∼4′, and the shortest baseline of 3.8 m prevents a serious missing flux. Fringes are detected for several radio sources, including the sun and Cas A. After a rough relative calibration, we have derived visibilities for the sun, whose amplitudes are decreasing for longer baselines. We have made a solar image using the visibility amplitudes and closure phases, referring to the 17 GHz image by Nobeyama Radioheliograph. Developing a flexible real-time correlator seems most crucial if this kind of the system is to be used for more rigorous scientific studies.