  The Jiao Tong University Spectroscopic Telescope (JUST) is a 4.4-meter f/6.0
segmentedmirror telescope dedicated to spectroscopic observations. The JUST
primary mirror is composed of 18 hexagonal segments, each with a diameter of
1.1 m. JUST provides two Nasmyth platforms for placing science instruments. One
Nasmyth focus fits a field of view of 10 arcmin and the other has an extended
field of view of 1.2 deg with correction optics. A tertiary mirror is used to
switch between the two Nasmyth foci. JUST will be installed at a site at Lenghu
in Qinghai Province, China, and will conduct spectroscopic observations with
three types of instruments to explore the dark universe, trace the dynamic
universe, and search for exoplanets: (1) a multi-fiber (2000 fibers)
medium-resolution spectrometer (R=4000-5000) to spectroscopically map galaxies
and large-scale structure; (2) an integral field unit (IFU) array of 500
optical fibers and/or a long-slit spectrograph dedicated to fast follow-ups of
transient sources for multimessenger astronomy; (3) a high-resolution
spectrometer (R~100000) designed to identify Jupiter analogs and Earth-like
planets, with the capability to characterize the atmospheres of hot exoplanets.
