Cosmology Large Angular Scale Surveyor (CLASS): pointing stability and beam measurements at 90, 150, and 220 GHz

Rahul Datta; Michael K. Brewer; Jullianna D. Couto; Joseph R. Eimer; Yunyang Li; Zhilei Xu; John W. Appel; Ricardo Bustos; David T. Chuss; Joseph Cleary; Sumit Dahal; Thomas Essinger-Hileman; Jeffrey Iuliano; Tobias A. Marriage; Carolina Nunez; Matthew A. Petroff; Karwan Rostem; Duncan J. Watts; Edward J. Wollack

doi:10.1117/12.2630649

31 August 2022 Cosmology Large Angular Scale Surveyor (CLASS): pointing stability and beam measurements at 90, 150, and 220 GHz

Rahul Datta, Michael K. Brewer, Jullianna D. Couto, Joseph R. Eimer, Yunyang Li, Zhilei Xu, John W. Appel, Ricardo Bustos, David T. Chuss, Joseph Cleary, Sumit Dahal, Thomas Essinger-Hileman, Jeffrey Iuliano, Tobias A. Marriage, Carolina Nunez, Matthew A. Petroff, Karwan Rostem, Duncan J. Watts, Edward J. Wollack

Author Affiliations +

Proceedings Volume 12190, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI; 121902S (2022) https://doi.org/10.1117/12.2630649
Event: SPIE Astronomical Telescopes + Instrumentation, 2022, Montréal, Québec, Canada

Conference Poster

Abstract

The Cosmology Large Angular Scale Surveyor (CLASS) telescope array surveys 75% of the sky from the Atacama desert in Chile at frequency bands centered near 40, 90, 150, and 220 GHz. CLASS measures the largest-angular scale (θ ≳ 1 ◦ ) CMB polarization with the aim of constraining the tensor-to-scalar ratio, r, measuring the optical depth to reionization, τ , to near the cosmic variance limit, and more. The CLASS Q-band (40 GHz), W-band (90 GHz), and dichroic high frequency (150/220 GHz) telescopes have been observing since June 2016, May 2018, and September 2019, respectively. On-sky optical characterization of the 40 GHz instrument has been published. Here, we present preliminary on-sky measurements of the beams at 90, 150, and 220 GHz, and pointing stability of the 90 and 150/220 GHz telescopes. The average 90, 150, and 220 GHz beams measured from dedicated observations of Jupiter have full width at half maximum (FWHM) of 0.615±0.019◦ , 0.378±0.005◦ , and 0.266 ± 0.008◦ , respectively. Telescope pointing variations are within a few % of the beam FWHM.

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Rahul Datta, Michael K. Brewer, Jullianna D. Couto, Joseph R. Eimer, Yunyang Li, Zhilei Xu, John W. Appel, Ricardo Bustos, David T. Chuss, Joseph Cleary, Sumit Dahal, Thomas Essinger-Hileman, Jeffrey Iuliano, Tobias A. Marriage, Carolina Nunez, Matthew A. Petroff, Karwan Rostem, Duncan J. Watts, and Edward J. Wollack "Cosmology Large Angular Scale Surveyor (CLASS): pointing stability and beam measurements at 90, 150, and 220 GHz", Proc. SPIE 12190, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI, 121902S (31 August 2022); https://doi.org/10.1117/12.2630649

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