Spectrograph
In spectroscopy mode, the user is offered a choice of one of three instruments of the Spectrograph Block:
VUVES – vacuum UV echelle spectrograph (VUVES) for operation in the spectral range 115 - 176 nm with resolution R = 50000
UVES – UV spectrograph (UVES) for operation in the spectral range 174 – 310 nm with resolution R = 50000
LSS – long-slit spectrograph (LSS) for obtaining low-resolution spectra (R = 1000) of point and extended objects in the range 115 - 315 nm
Technical specifications of the spectrograph measurement channels:
| Parameter Name | VUVES | UVES | LSS |
|---|---|---|---|
| Working Spectral Range, nm | 115–176 | 174–310 | 115–315 |
| Spectral Resolution | ~50000 | ~50000 | ~1000 |
| Spectral Resolution with Full Slit Fill (for extended sources) | ~20000 | ~20000 | ~1000 |
| Slit Size, " | 1 | 1 | 1×72 |
| Detector Type | CCD | ||
| Gradient Anti-Reflection Coating of CCD | No | Yes | Yes |
| Photosensitive Area Size, mm | 37.3×49.1 | ||
| Detector Format, pixel | 3112×4096 | ||
| Image Scale, "/pixel | 0.134 | ||
| Pixel Size, microns | 12 | ||
| Read Noise, electrons | 3 | ||
| Dark Current, counts/s/pixel | 8.3E-4 | 3.3E-3 | 3.3E-3 |
Quantum Efficiency of Spectrograph Detectors
Throughput of Spectrographs
LSS Spectrograph
Spectrograph Dispersion, Å/pixel
LSS Spectrograph
