The estimate of sensitivity for large infrared telescopes based on measured sky brightness and atmospheric extinction

In order to evaluate the ground-based infrared telescope sensitivity affected by the noise from the atmosphere, instruments and detectors, we construct a sensitivity model that can calculate limiting magnitudes and signal-to-noise ratio (S/N). The model is tested with tentative measurements of M �...

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Bibliographic Details
Published in:Research in Astronomy and Astrophysics
Main Authors: Zhao, Zhi-Jun, Zhou, Hai-Jing, Zhang, Yu-Chen, Ling, Yun, Xu, Fang-Yu
Format: Report
Language:English
Published: NATL ASTRONOMICAL OBSERVATORIES, CHIN ACAD SCIENCES 2021
Subjects:
methods
miscellaneous
atmospheric effects
telescopes
site testing
instrumentation
detectors
Astronomy & Astrophysics
LARGE OPTICAL/INFRARED TELESCOPE
TESTING CAMPAIGN
SOUTH-POLE
SITE
South Pole
South pole
Online Access:http://ir.ynao.ac.cn/handle/114a53/24468
https://doi.org/10.1088/1674-4527/21/4/81
Description
Summary:In order to evaluate the ground-based infrared telescope sensitivity affected by the noise from the atmosphere, instruments and detectors, we construct a sensitivity model that can calculate limiting magnitudes and signal-to-noise ratio (S/N). The model is tested with tentative measurements of M '-band sky brightness and atmospheric extinction obtained at the Ali and Daocheng sites. We find that the noise caused by an excellent scientific detector and instruments at -135 degrees C can be ignored compared to the M '-band sky background noise. Thus, when S/N = 3 and total exposure time is 1 second for 10 m telescopes, the magnitude limited by the atmosphere is 13.01(m) at Ali and 12.96(m) at Daocheng. Even under less-than-ideal circumstances, i.e., the readout noise of a deep cryogenic detector is less than 200e(-) and the instruments are cooled to below -87.2 degrees C, the above magnitudes decrease by 0.056(m) at most. Therefore, according to observational requirements with a large telescope in a given infrared band, astronomers can use this sensitivity model as a tool for guiding site surveys, detector selection and instrumental thermal-control.

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