Manchester Echelle Spectrometer-Aristarchos Telescope (MES-AT)


This high resolution spectrometer is dedicated to the investigation of extended line-emission phenomena (i.e. Supernova remnants, Planetary nebulae, HII regions, Luminous blue variable star’s nebulae etc). The instrument is not currently available to the observers.


In its primary mode a single order of its echelle grating nominally δ=63.54˚ with 31.6 grooves/mm is isolated by a broad, efficient, three period interference filter eliminating the need of cross-dispersion. Consequently, its primary use, is to obtain spatially-resolved profiles of individual emission lines from faint extended sources emitting in the range 3900-7500 Ǻ with a spectral resolving power of λ/Δλ ≤105.

Several secondary mode are available:

A direct image of the field can be obtained by both the insertion of a clear to replace the slit and of a mirror before the grating (slit positions against images of extended sources can be obtained using this facility). The insertion of a grism along with the plane mirror permits long-slit, low dispersion (76.3 Ǻ/mm) spectra to be obtained.

Parameters on the Aristarchos 2.3 m telescope (first calculated values)

Slit widths Option 1 Option 2
Option 3
(μm) 70 150 300
(km/s) 5 10 20
(arcsec) 0.8 1.8 3.5
multi-slits number of slits free spectral range sky separation
  10 1.65 mm = 138 km/s =19.2 arcsec
  5 3.3 mm = 138 km/s =38.4 arcsec
  3 6.6 mm = 138 km/s =76.9 arcsec
slit length linear on sky comments
  30 mm 5.8 arcmin curent max.
  60 mm 11.6 arcmin  
Other isolatator filter center (bandwidth) centre (bandwidth) centre (bandwidth)
  6730 (100) Å 6580 (100) Å 5020 (70) Å
echelle grating blaze angle grooves/mm ruled area
  63.54 deg 31.6 128x254
  Dispersion Spectral range  
  76.3 Å/mm 4500-6750Å  
Field area (max) Linear On sky Scale
Current 24.6x24.6 mm 4.8x4.8 arcmin2 0.3 arcsec/pixel
max 25x30 mm 4.9x5.8 arcmin2