Pointing and Focus Corrections 汇报人：肖 明 (研究生2年) 邮 箱：xiaoming@xao.ac.cn 地 址：新疆天文台(202室)

THE PARABOLOIDAL REFLECTOR ANTENNA IN RADIO ASTRONOMY Geometry of reflector antennas Electromagnetic theory of the reflector antennas Antennas’ characteristics in practical applications (1).Aperture illumination (2).Axial defocus (3).Lateral defocus (4).Aperture blockages (5).Surface tolerance theory Measurement of antenna parameters (1).Pointing and focus corrections √ (2).Extraterrestrial sources as test transmitters 5. Miscellaneous subjects (1).Holographic measurement (2).Off-set aperture (3).Atmospheric fluctuations

Pointing and focus corrections Mono-pulse The principle of the mono-pulse technique is simple. The feed-horns of the mono-pulse tracker are slightly displaced so that each receives the signal from a slightly different position, that is, at slightly different power. Scanning (1). Conical Scan (2). Lissajous Scan (3). Rosette Scan

Performance Evaluation Encode position disturbances (1). random disturbances (2). deterministic disturbances Measured power disturbances

the Conclusion They show that for frequencies higher that the scanning frequency the disturbances are quickly suppressed.

Next to talk about some SCIENCE

The Sunyaev–Zel’dovich (SZ) Effect in Cosmology and Cluster Physics The Physics of the Sunyaev-Zel’dovich Effect (1). Thermal SZ Effect [GBT] (2). Kinematic SZ Effect [ALMA] Observing the Sunyaev–Zel’dovich Effect √ Cluster Science from the Sunyaev–Zel’dovich Effect Cosmology from the Sunyaev–Zel’dovich Effect

Much better results should be obtained using two-dimensional arrays of detectors, as should be available on the Green Bank Telescope when it is completed. QTT

QTT XAO China GBT U.S. ALMA U.S. Japan Taiwan ACT Penn. U.S. APEX-SZ Berkeley U.S. SPT Chicago U.S. Higher sensitivity Higher resolution

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