WES - Weihai Echelle Spectrograph

TL;DR

The Weihai Echelle Spectrograph (WES) is China's first fiber-fed echelle spectrograph, designed for stellar studies and exoplanet detection, offering high spectral resolution and precise radial velocity measurements.

Contribution

This paper introduces WES, the first fiber-fed echelle spectrograph in China, detailing its design, performance, and capabilities for astronomical research.

Findings

Spectral coverage from 371 to 1100 nm across 107 orders.

Spectral resolution adjustable from 40,600 to 57,000.

Radial velocity measurement accuracy better than 10 m/s over 10 months.

Abstract

The Weihai Echelle Spectrograph (WES) is the first fiber-fed echelle spectrograph for astronomical observation in China. It is primarily used for chemical abundance and asteroseismology studies of nearby bright stars, as well as radial velocity detections for exoplanets. The optical design of WES is based on the widely demonstrated and well-established white-pupil concept. We describe the WES in detail and present some examples of its performance. A single exposure echelle image covers the spectral region 371-1,100 nm in 107 spectral orders over the rectangular CCD. The spectral resolution $R=\lambda/\Delta\lambda$ changes from 40,600 to 57,000 through adjusting the entrance slit width from full to 2.2 pixels sampling at the fiber-exit. The limiting magnitude scales to $V=8$ with a signal-to-noise ratio (SNR) of more than 100 in $V$ for an hour exposure, at the spectral resolution R$\approx$40,000 in the median seeing of 1.7$^{\prime\prime}$ at Weihai Observatory (WHO) for the 1-meter telescope. The radial velocity (RV) measurement accuracy of WES is estimated to be $<$10 m/s in 10 months (302 days) and better than 15 m/s in 4.4 years (1,617 days) in the recent data processing.