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About the Telescope and Instrument

Effective Aperture: 2.16m

Primary mirror focal ratio: f/3

Cassegrain focal ratio: f/9

Coude focus ratio: f/45

Telescope mount: Equatorial


Three instruments:

BFOSC (Beijing-Faint Object Spectrograph and Camera)

OMR Low Resolution Spectrograph

HRS (High Resolution fiber-fed Spectrograph)

BFOSC (Beijing-Faint Object Spectrograph and Camera)

Cassegrain focal ratio: f/9

FOV= 9'.46×8'.77

CCD55-30-1-348 back, AIMO, CCD controller was made by Lick Observatory.

CCD size: 1242×1152 pixel

Pixel scale: 0".457

Pixel size: 22.5 μm

Focal plane scale: 10.61”/mm


Fig. 2. Observing mode of 2.16m BFOSC


Fig. 2.  Observing mode of 2.16m BFOSC

For the imaging

The Johnson UBVRI and 385LP band and Z band are mounted.

Fig. 3. The filter response functions of the broadband for 2.16m BFOSC system

Fig. 3. The filter response functions of the broadband for 2.16m BFOSC system

In addition, we have a series of interference narrow band filters of H-alpha, [OIII] and He with radial velocities up to 20,000km/s.

Fig. 4. Filter response functions of 2.16m BFOSC (narrow band)

Fig. 4.  Filter response functions of 2.16m BFOSC (narrow band)



For the spectrograph:

It has the long slits (9'.4) and short slits(3″.5-4″.0) observing modes.


Table 1. The current parameters of BFOSC gratings


The current thinned BFOSC CCD has high QE in the blue band and a new CCD, which has high QE in the red band, will replace it.


Fig. 5.  The QE of the current BFOSC CCD

It also has the slitless spectroscopic mode for the multi-object observations.

From the year of 2012, with the new facility, the mask observation mode has been available. Usually 10-20 objects can be observed simultaneously.

OMR Low Resolution Spectrograph

The Optical-Mechanism Research Low Resolution Spectrograph (OMR) is another low-intermediate resolution spectrograph in 2.16m telescopes, which is also mounted on the Cassegrain focus. It is composed of spectrograph, CCD camera, guiding camera, console and data collecting PC.




Fig. 6.  OMR Low Resolution Spectrograph

HRS (High Resolution Fiber-fed Spectrograph)

High Resolution Fiber-fed Spectrograph (HRS) is developed by the Nanjing Institute of Astronomical Optics & Technology (NIAOT) in October, 2010 to satisfy the scientific requirement of extro-planets survey, research of stellar abundances, research of stellar magnetic activity etc. (see Fig. 7).

 

HRS can be switched between the existing equipment and itself by the Cassegrain focal interface of the telescope. The calibration system of HRS, the I2 cell with its heating system, and the incoming Tip/Tilt system all mounted or will mount on this interface. The main body of HRS is set in a protective box (see Fig. 8 and Fig. 9), in which the temperature stability is better than 0.5°C during one week. Further parameters of HRS please see table 4.

 

Ongoing improvement project for HRS:

1.         Second phase schedule of HRS

(1)      Add 1″.6 fiber and Tip/Tilt system for HRS (which will be finished before March, 2014)

      To satisfy the requirement for deferent resolution observation and improve the efficiency for different seeing

(2)      An environmental control system for HRS  (which will be finished before September, 2014)

      It is under construction, which could accurately control the pressure, temperature, and humidity for HRS of the Xinglong 2.2m telescope. The key components are delivered. The construction of the whole system will be finished in the end of 2013.

2.         An astro-frequency comb (which will be finished before May, 2014)

(1)      Scientific requirement for an astro-frequency comb

      High precision radial velocity measurement

(2)      Advantage to the I2 cell (Wilken et al. 2010)

      Thousands of uniformly spaced lines with equal intensity

      Keeplines stable and reproducible for long time scale

      Clean spectra

(3)      Progress of the astro-frequency comb adjustment

An astro-frequency comb, which will greatly improve the precision of HRS, had been developed by Peking University and shipped to Xinglong Observatory. The comb was setup and the first spectrum simultaneously from the comb and the flat lamp has been obtained during the engineering run.

Fig. 7.  The light-path of HRS



Fig. 8.  The protective box for HRS


Fig. 9.  HRS adjusting by a laser lamp-house





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