 OMR Cassegrain spectrograph
OMR Cassegrain spectrograph was manufactured by Opto-Mechanics Research,
Inc. in the United States. Fig.2 is the optical layout of the spectrograph.
The light beam from the telescope passes through the slit, and after
the collimator, is reflected on to the grating and finally imaged by
a camera onto the CCD chip.
The focal length of the collimator and camera is 674mm and 150mm, respectively. The spectrograph is remote controlled by computer and/or the control console in control room.
The slit assembly consists of two polished and aluminized stainless steel jaws on which the observational field with field of view of 4' X 4' is reflected back onto couple of lenses, finally imaged on the guiding CCD ( Model: STAR-1 from Photometrics, Ltd.). The image from STAR-1 is shown at a monitor located in control room.
Comparison sources are provided for wavelength calibration. They are He/Ne, Fe/Ne. Fe/Ar lamps. The standard wavelength of calibration lines can be found in control room.
There are six gratings available for the OMR spectrograph. Dispersions
range from 5nm/mm to 40nm/mm in first order. Gratings can be changed
easily, but change gratings during the observations at night is not
recommended.
The WET standard 3-channel high speed photometer
This photometer was upgraded from a 2-channel photometer, it is designed for investigating pulsating white dwarf stars and other short period variable phenomena. Since it was originally designed in McDonald Observatory for the Whole Earth Telescope (WET) campaigns (Nather, et al, 1990), so it is named as WET standard photometer.
The WET standard photometer can be attached to 2.16m and 85cm telescopes at Xinglong Station, the limiting magnitudes at the 2.16m and 85cm telescopes are V=17.5 and V=15.5, respectively.
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