CGS4 Filters
   
Up:
CGS4Handbook
CGS4 Filters
The following two tables list the filters in use with CGS4, their
central wavelengths and cut-on and off wavelengths (half power).
Broad Band Filters (for low and medium resolution gratings):
| Filter Name |
Central Wavelength (µm) |
Cut-on Wavelength (µm) |
Cut-off Wavelength (µm) |
Throughput at Central Wavelength (%) |
Estimated Average Throughput1 (%) |
| IJ |
0.94 |
0.84 |
1.04 |
55 |
48 |
| B1 |
1.29 |
0.99 |
1.59 |
83 |
84 |
| B2 |
2.02 |
1.43 |
2.60 |
92 |
89 |
| B3 |
3.15 |
2.14 |
4.16 |
90 |
93 |
| B4 |
3.50 |
2.75 |
4.24 |
90 |
88 |
| B5 |
4.92 |
4.35 |
> 5.5 |
93 |
92 |
| B6 |
2.21 |
2.00 |
2.41 |
78 |
74 |
1 Estimated in the central 75% of the bandpass.
Narrow Band Filters (echelle mode):
| Filter Name |
Central Wavelength (µm) |
Cut-on Wavelength (µm) |
Cut-off Wavelength (µm) |
Throughput at Central Wavelength (%) |
| N1 |
1.089 |
1.078 |
1.099 |
57 |
| N22 |
1.229 |
1.218 |
1.240 |
62 |
| N3 |
1.259 |
1.247 |
1.272 |
62 |
| N4 |
1.275 |
1.264 |
1.286 |
59 |
| N5 |
1.293 |
1.283 |
1.305 |
66 |
2 The N2 filter is not currently installed in CGS4's filter
wheels.
For wavelengths beyond 1.3-µm, the CVFs are used as order-blockers
when using the echelle. When the new wedged CVFs are installed, the narrow
band filters will no longer be necessary, as one of the CVF segments will
extend down to 0.93 um.
Last Modification Date: 1998/08/04 - Last Modification Author: Tom
Kerr
Tom Kerr (tkerr)
|
