 
 
Nasmyth Echelle Spectrograph (NES) 
 The echelle spectrograph NES located at the Nasmyth-2 focus (1:30)
 platform   of   the  6-m  telescope  is a part
 of the spectral complex ( MSS ,
  LYNX , NES) having a common control.
 Development of the echelle spectrograph NES was performed in the
 framework of the  
 SAO-programme "Modernization of the 6-m telescope".  
 This  spectrograph  was designed by
V.E. Panchuk,
V.G. Klochkova,
 I.D. Najdenov
and Prof. N.E. Piskunov (Uppsala University).
  Optical  elements were produced mainly at the Vavilov Optical
Institute and the Optic-Mechanical Corporation, St.Petersbourgh. 
This spectrograph  provides a spectral resolution R=60000.  
Its optical layout (without preslit devices) is presented
  here .
 The  preslit devices are presented
  here .
 
 The  focal  length  of  the collimator  is  F=7200mm. The diameter of the
 collimated beam is d=240mm.
 The  mosaic R2 echelle 600x300mm, 37.5 gr/mm is used in
 the quasi autocollmation mode.  
 The gratings for cross dispersion have 300 and 600 gr/mm, the  blazed area
 is 320x360mm.
 The Schmidt-Cassegrain camera's focal length is F=600mm,  the diameter of
 the correction plate is D=305mm. Whole camera's optics, including
 double-pass back alluminated Cassegrain menisc, is made from fused silica.
 The diameter of the flat field of this camera is about 40mm.
 The first light of the NES was obtained with the CCD 1040x1160 pixels,
with the pixel size 16x16mkm. This CCD was developed by the 
 ADL SAO.    
 
 In July 2001 the  large
    CCD   2050x2050  producted in Denmark was installed at  the
     NES. The CCD works inside the LINUX
    environment under the software BIAS developed in Copenhagen
    University Observatory, Denmark.
 We present here some spectra obtained at the 6m telescope
    using the spectrograph NES in combination with a CCD 2050x2050:
    high resolution, R=60000, spectrum of
    
    subdwarf G27-44  (B=8.0) in the blue spectral range 3500-5000 AA 
   and 
   high resolution, R=60000, spectrum  of
   
   peculiar star HD4778 
   obtained in the spectral range 4700-6100 AA with a Zeeman analyzer.
 
  
The description of NES
(PostScript-file,  in Russian)  is applied. Besides, some details
of the construction and results of a testing are published in the
SAO Preprints, 1999, N135, 137 and 138.
The results of adaption of a large "Uppsala" CCD 2048x2048 pixels 
are presented by Panchuk V.E., Piskunov N.E., Klochkova V.G., Yushkin M.V. and Ermakov S.V. 
in the SAO    Preprint N169, 2002  (in Russian).  
There are  positional, photometric parameters of the spectrometer, the parameters
of the echelle frame, the sample of observations, etc.     
 
   
 
 Recent full description of the spectrograph NES is pesented in the paper
by V.Panchuk, V.Klochkova, M.Yushkin & I.Najdenov.
Journal Optical technology, 2009, v.76, p.87.   
In Russian: В.Е.Панчук, В.Г.Клочкова, М.В.Юшкин, И.Д.Найденов,
Оптический журн., т.76, с.42 (2009).   
 A current state of the NES spectrograph is presented in the published  paper  by V.E.Panchuk, V.G.Klochkova, M.V.Yushkin, 
Echelle spectrograph gfor the 6-meter telescope BTA. Astron. Rep., 
v.61, 820-831, 2017.  
 
 
 To consult or request, please, contact with
Prof. Vladimir Panchuk: 
panchuk@sao.ru 
Here we present some NES-spectra: 
 
 
The spectrum of the same dwarf  we derived with the BTA+NES in
combination with the Jodine cell 
 
