Proceedings Article | 18 July 2024
Shogo Otsubo, Yuki Sarugaku, Tomomi Takeuchi, Yuji Ikeda, Noriyuki Matsunaga, Andrew McWilliam, Charlie Hull, Tomohiro Yoshikawa, Haruki Katoh, Sohei Kondo, Satoshi Hamano, Daisuke Taniguchi, Hideyo Kawakita
KEYWORDS: Telescopes, Observatories, Spectrographs, Spectral resolution, Infrared spectroscopy, Astronomy
WINERED is a PI-type near-infrared (z, Y, J-bands) high dispersion spectrograph developed by Koyama Astronomical Observatory of Kyoto Sangyo University and the University of Tokyo (Ikeda et al. 2022). In 2022, WINERED was moved to the 6.5-m Magellan II - Clay telescope at Las Campanas Observatory (LCO) to take advantage of its extremely high sensitivity (the instrumental total throughput ~60%), which is its best feature, and started scientific observations in 2023. This paper presents the details of the development undertaken for the relocation, the instrumental performance when attached to the Magellan telescope, and its operational structure and strategy. For the relocation to LCO, a new instrument transport cart was manufactured. This allows for installation on the Nasmyth platform within 30 minutes, without the need of special alignment tasks, and with highly reproducible accuracy. Since the 125mm back-focal length of the Magellan telescope was too short for WINERED, a new focal extender was fabricated and introduced to ensure proper focus on the slit. In addition, an original guider system was constructed by combining the Auto-Guider function of the Magellan telescope and WINERED's pre-existing slit viewer, and it was confirmed that a tracking accuracy of about 0.1 arcsec was achieved. This new guider system, which provides a function such as automatic dithering, has been highly regarded by observers, especially for remote observations which have become increasingly essential since the Covid-19 pandemic. Up to this point, utilizing WINERED on Magellan telescope, we have been able to obtain spectra with an SNR=30 (R=28,000) for a point source as faint as J=16 mag with just 1-hour of exposure even under a natural seeing condition. This sensitivity exceeds that of infrared high dispersion spectrographs on a 10-m class telescope, even though these spectrographs are usually utilized with AO. Currently, WINERED is operated under the collaboration of the Carnegie Observatories and LCO with the WINERED team responsible for the setup of the instrument, observing support in night time, and initial data reduction including the provision of data-reduction pipeline. As compensation, 20% of the total observation time, equating to 6 nights in the achievement of 2023, has been allocated to the WINERED team.
