The diffraction gratings (grisms)
The spectrograph has a set of grisms with a Volume Phase Holographic Gratings
(VPHG), which are manufactured by Wasath Photonics (USA)
The quantum efficience of the different grisms. The SCORPIO-2 optical transparency and CCD E2V 42-90 QE curve are taken into account. The best measurements of the standard stars are shown for the wide (more than 10'') slit. The second order contamination for the VPHG940@600 was partly removed
The SCORPIO-2 grisms parameters
Name | lines/mm | Spectral range, A | Dispersion, A/px | Sp. resolution (FWHM), A |
| | | | slit 1" | slit 0.7" | slit 0.5" |
VPHG940@600 | 940 | 3500-8500 | 1.16 | 7.0 | 5.0 | 3.5 |
VPHG1026@735 | 1026 | 5800-9500 | 1.02 | 6.1 | 4.3 | 3.0 |
VPHG1200@540 | 1200 | 3650-7250 | 0.87 | 5.2 | 3.6 | 2.6 |
VPHG1800@590 | 1800 | 5000-7245 | 0.50 | 3.0 | 2.1 | 1.5 |
VPHG1800@660 | 1800 | 5500-7800 | 0.51 | 3.0 | 2.1 | 1.5 |
VPHG2400@415* | 2400 | 3500-5100 | 0.36 | 2.2 | 1.5 | 1.1 |
VPHG3000@400 | 3000 | 3700-4400 | 0.32 | 1.9 | 1.3 | 1.0 |
VPHG1200@860 | 1200 | 7445-10900 | 0.85 | 5.1 | 3.6 | 2.5 |
* - the grism can be used only in spectropolarimetry mode
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