UIST: Engineering: Grism Wheels 2003-2004
UIST has two 9-slot grism wheels which contain the polarimetry prism and the grisms for spectroscopy. The table below lists the grism wheels’ population. See the UIST filter-wheels web page for cut-on/cut-off wavelengths for the filters. Note that the short-/long- grisms are used in second order, so some ofthe blocking filter choices are driven by the need to block different orders (e.g. 2nd order lines between 1.34-1.51 passed by the B2 would appear in the short-K grism in 3rd order [at 2.00-2.26], so the short-K cutoff must be >1.51um; similarly, 2nd order lines between 1.58-1.67 would come through the HK filter and be seen by long-K in 3rd order [at 2.37-2.51], so the long-K blocker cut-off must be >1.67um).
1 March 2003 — 9 March 2004
Wheel 1 | Wheel 2 | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Posn | Grism | Ref. | Weight | Blocker | Posn | Grism | Ref. | Weight | Blocker | ||
1 | open | — | — | — | 1 | open | — | — | — | ||
2 | Short J | 54 | 242.4 | J-spectral | 2 | HK low* | 84 | 169.7 | non | ||
3 | Wollaston | 81 | 225 | — | 3 | Long J | 53 | 250 | J-spectral | ||
4 | Short L | 59 | 217.4 | L-spectral | 4 | HK | 83 | 181.4 | B2 (cgs4) | ||
5 | blank | — | 221.7 | — | 5 | Short K | 56 | 250 | HK-spectral | ||
6 | KL | 57 | 205 | KL-spectral | 6 | Long H | 51 | 241.2 | H-spectral | ||
7 | Short H | 52 | 250 | H-spectral | 7 | IJ | 85 | 160.0 | none | ||
8 | Long K | 55 | 251.4 | KL-spectral | 8 | Long L | 58 | 235 | L-spectral | ||
9 | HK x-disp | 86 | 159.5 | none | 9 | M | 60 | 230 | M-spectral |
*Used with the HK cross-disperser (so no need for blocking)
Movement between positions 5 or 6 and the other positions involves moving passed a datum switch.
Previous grism wheel arrangements: Pre-20030301.