Echelle spectrograph
The Reosc Echelle Spectrograph provides high dispersion spectra (from 5 Å/mm in the far blue to 10 Å/mm at 6000 Å), with cross-dispersion provided by a grating. The spectrograph can also be used in normal dispersion mode by replacing the echelle grating with a flat mirror and interchanging the slit and comparison lamp slots. The use of the latter configuration is not however encouraged.
Echelle technical data
| Collimator Focal Length | 721.8 mm |
| Collimator Off axis parabola | 90x110 mm |
| Beam Diameter | 83 mm |
| Camera Focal Length | 204 mm |
| Camera Flat Focal Plane | 8x5 degree |
| Wavelength Coverage | - nm |
| Limiting Spectral Resolution | 28600 (0.7 arcsec slit) |
|
grating type ll/mm
|
Blaze (Å)
|
Dispersion (Å/mm)
|
Spectral Purity (Å)
|
Spectral Range (Å)
|
|
79 (echelle R2)
|
4990
|
7.3
|
0.2
|
|
|
150(CD1)
|
8000
|
327
|
4.9
|
|
|
300 (CD2)
|
4980
|
163
|
2.5
|
|
|
1200 (CD3)
|
5977
|
39
|
0.6
|
|