Pointing Calibration of GroundBIRD Telescope Using Moon Observation Data

Journal article (2024)

Authors

Y. Sueno Graduate School of Science
J.J.A. Baselmans Tera-Hertz Sensing - EEMCS , SRON–Netherlands Institute for Space Research
A. Coppens SRON–Netherlands Institute for Space Research
R. T. Génova-Santos Instituto de Astrofísica de Canarias, Universidad de la Laguna
M. Hattori Tohoku University
K. Karatsu SRON–Netherlands Institute for Space Research
K. Lee Student, Korea University
J. Suzuki Graduate School of Science
David Thoen SRON–Netherlands Institute for Space Research
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Research Group
Tera-Hertz Sensing (EEMCS) (TU Delft)
Copyright: © 2024 Y. Sueno, J.J.A. Baselmans, A. Coppens, R. T. Génova-Santos, M. Hattori, K. Karatsu, K. Lee, J. Suzuki, David Thoen, More Authors
DOI: https://doi.org/10.1093/ptep/ptae011
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Published Date

2024

Language

English

Faculty

Electrical Engineering, Mathematics and Computer Science

Department

Microelectronics

Research Group

Tera-Hertz Sensing

Abstract

Understanding telescope pointing (i.e. line of sight) is important for observing the cosmic microwave background (CMB) and astronomical objects. The Moon is a candidate astronomical source for pointing calibration. Although the visible size of the Moon (30`) is larger than that of the planets, we can frequently observe the Moon once a month with a high signal-to-noise ratio. We developed a method for performing pointing calibration using observational data from the Moon. We considered the tilts of the telescope axes as well as the encoder and collimation offsets for pointing calibration. In addition, we evaluated the effects of the nonuniformity of the brightness temperature of the Moon, which is a dominant systematic error. As a result, we successfully achieved a pointing accuracy of 3.3`. This is one order of magnitude smaller than an angular resolution of 36`. This level of accuracy competes with past achievements in other ground-based CMB experiments using observational data from the planets.