The tables below contain the set of filters currently available for INGRID. All filters have been purchased in collaboration with the Gemini filter buying consortium (headed by Alan Tokunaga). Their specifications are described here.
All the filters has been scanned and the transmission curves are available as graphs or as ASCII files linked in the tables below. Note that the scans have been obtained at room temperature (~293K) and at 0 degrees angle with respect to the incident light. The central wavelength of the narrowband filters depends on the angle of incidence and on the temperature (~5 degs and 77K for INGRID, respectively). The data labelled as 'cold' in the tables has been calculated (from the measured scans) as described here, but does not represent direct measured data from the filters.
Click on the red or blue dots to get the transmission curves measured (warm) or estimated (cold) for the temperature of INGRID.
Important note: Please be aware that filter Br-gamma is redshifted by ~4nm with respect to the rest-frame wavelength of the corresponding emission line.
INGRID broad band filters (filter wheel 1) |
Filter name | Central wavelength (µm) |
Width (fwhm) (µm) |
50% transmission cut on/off (µm) |
Peak transm.(%) |
Transm. curve (warm) |
Transm. data (warm) |
Comments |
|---|---|---|---|---|---|---|---|
| Z | 1.033 | 0.073 | 0.996/1.069 | 88 |
 |
|
non-AO specified (i) |
| J | 1.250 | 0.160 | 1.170/1.330 | 90 |
|
|
- |
| H | 1.635 | 0.290 | 1.490/1.780 | 87 |
|
|
- |
| H-Barr | 1.635 | 0.290 | 1.490/1.780 | 97 |
|
|
- |
| K | 2.200 | 0.335 | 2.028/2.364 | 95 |
|
|
- |
| Ks | 2.150 | 0.310 | 1.990/2.300 | 95 |
|
|
- |
| Ks-Barr | 2.150 | 0.320 | 1.990/2.310 | 89 |
|
|
- |
INGRID narrow band filters (ii) (filter wheel 2) |
Filter name | Central wavelength (µm) |
Width (fwhm) (µm) |
Peak transm. (%) |
Transm. curve warm cold |
Transm. data warm cold |
CWL change with T (nm/oC) |
Emission line (iv) (µm) |
Comments |
|---|---|---|---|---|---|---|---|---|
| UCM | 1.182 | 0.0092 | 73 |
 |
|
0.0014 | - | Private filter (contact J. Zamorano/J. Gallego: jaz/jgm@astrax.fis.ucm.es) |
| J-cont | 1.209 | 0.018 | 63 |
|
|
0.0318 | - | - |
| Pa-beta | 1.283 | 0.020 | 71 |
|
|
0.0255 | 1.2818 | Replaced in March 2003 (iii) |
| H-continuum | 1.573 | 0.024 | 74 |
|
|
0.0311 | - | - |
| [Fe II] | 1.642 | 0.024 | 74 |
|
|
0.0311 | 1.6436 | - |
| H2 v=1-0 | 2.121 | 0.032 | 72 |
|
|
0.0396 | 2.121 | - |
| Br-gamma | 2.170 | 0.032 | 69 |
|
|
0.0732 | 2.1655 | Redshifted by ~4nm (iii) |
| H2 v=2-1 | 2.246 | 0.034 | 56 |
|
|
0.0439 | 2.247 | Replaced in March 2003 (iii) |
| K-continuum | 2.270 | 0.033 | 70 |
|
|
0.0756 | - | - |
(i) The order of the Z filter specified for AO observations has been cancelled.
(ii) The order of filters HeI (1.083/0.016µm) and Pa-gamma (1.094/0.016µm) has been cancelled.
(iii) The Pa-beta and H2v2-1 filters were replaced in March 2003. The Pa-beta and H2v2-1 filters in use
before March 2003 were out of specs, i.e. redshifted respectively by ~5 and 13nm with respect to the rest-frame
wavelength of the corresponding emission lines.
The redshift of the filter Br-gamma is within the specifications
of the filter.
(iv) Rest-frame emission line wavelength associated to each filter.
 |
Last Updated: 2 January 2004 Almudena Zurita azurita@ing.iac.es |