Wheels (Filters and Grisms)
The Mechanical design of EMIR is composeb by two wheels. One that carries the dispersion units (Grism Wheel) and another with the filters (Filter Wheel).
The Grism Wheel positionate the grism at the optical beam. There will be a total of 6 positions:
- Two clear apertures for imaging.
- One conventional grism.
- Three pseudo-grisms (J, H and K).
The Filters Unit follows the same design concept as the Grism Unit, carrying filters instead of grisms. There are 16 positions in the wheel, 14 for filters, a clear aperture and a closed position (the disc itself blocks the light in a position where no aperture is machined).
The filters available are the 6 broad band filters (Y, J, H, K, K-short and K-spect), 6 narrow band filters (Brackett-Gamma; FeII; and their continunm filters; H2(1-0) and H2(2-1) respectively) and 2 order sorting filters for low resolution spectroscopy (YJ and HK).
|
FILTER |
Central λ |
FWHM |
|
Y |
1031,5 |
133 |
|
J |
1253,25 |
159,5 |
|
H |
1629 |
281 |
|
K-short |
2160 |
312 |
|
K |
2234 |
322 |
|
K spect |
2214,25 |
426,5 |
|
Fell |
1646,75 |
29,5 |
|
Cont. Fell |
1714,35 |
26,7 |
|
Brackett-gamma |
2175,5 |
35 |
|
Cont. Br-gamma |
2126,5 |
30 |
|
H2 (1-0) |
2125,25 |
30.5 |
|
H2(2-1) |
2249 |
29 |
|
YJ |
1114,75 |
431,5 |
|
HK |
1929,25 |
951,5 |
