New auroral spectrometer using an acousto-optic tunable filter

• Main Authors: Kazuo Shiokawa, Yasuo Katoh, Mitsugi Satoh, Tadahiko Ogawa, Makoto Taguchi, Hisao Yamagishi
• Format: Report
• Language: English
• Published: Solar-Terrestrial Environment Laboratory, Nagoya University/Solar-Terrestrial Environment Laboratory, Nagoya University/Solar-Terrestrial Environment Laboratory, Nagoya University/Solar-Terrestrial Environment Laboratory, Nagoya University/National Institute of Polar Research/National Institute of Polar Research 2002
• Subjects: Syowa Station; Antarc*; Antarctica; Advances in polar upper atmosphere research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=6354; http://id.nii.ac.jp/1291/00006354/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=6354&item_no=1&attribute_id=18&file_no=1

This paper reports the performance and capability of a newly developed zenith spectrometer (for measurements of airglow and aurora) that uses an acousto-optic tunable filter (AOTF). The AOTF can scan the pass-band of the spectrometer between 450 and 700 nm with a bandwidth of 2-3 nm by changing the RF driver frequency from 180 to 100 MHz. The absolute sensitivity of the spectrometer is ～0.1-1.5 counts/Rayleigh/s per spectral step. The spectrometer is fully automated. The O I (557.7 nm) airglow line can be clearly identified in test observations of midlatitude airglow performed at Shigaraki Observatory, Japan. Based on an estimate of the signal-to-noise ratio, we conclude that the full auroral spectrum (450-700) nm can be measured by the AOTF spectrometer with a time resolution of ～100 s and a signal-to-noise ratio of ～100 for an auroral emission intensity of 10 kR. An example of the auroral spectra is shown for observations made at Syowa Station in Antarctica.