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 Å with a spectral resolving power of λ/Δλ ≤105.

Secondary modes

Several secondary modes 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 Å/mm) spectra to be obtained.

  • Status: To be commissioned

  • Detector: e2V 2kx2k

  • FOV: 4′.8×4′.8

  • Scale (“/pixel): 0.27

Manchester Echelle Spectrometer-Aristarchos Telescope (MES-AT)

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

Slit widths Option 1 Option 2 Option 3
(μm) 70 150 300
(R=λ/Δλ) 60,000 30,000 15,000
(Δλ at 6500 Å) 0.1 Å 0.2 Å 0.4 Å
(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 31.6 128×254
Dispersion Spectral range
76.3 Å/mm 4500-6750Å
Field area (max) Linear On sky Scale
Current 24.6×24.6 mm 4.8×4.8 arcmin2 0.3 arcsec/pixel
max 25×30 mm 4.9×5.8 arcmin2

MES-AR Schematic Representation

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