Reflective slits
Two reflective slits are available for IRCS grism mode. Each of the reflective slits has several width settings. There is a damaged portion within Reflective 4 slit which corresponds to 0.15" slit, and 0.3" slit for 20 mas, and 52 mas, respectively. It is strongly suggested not to use these slits. In general, 0.225" slits are recommended to be used as alternatives. Below are the images of Reflective 3W and 4 taken with both 20 mas and 52 mas mode.
Slits for 20 mas
Reflective 3W (0.45")
Reflective 4 (0.15", 0.1", 0.225")
The regions specified with green boxes are suitable for observations (other regions have damages in the surface coating and the efficiency is low).
Slits for 52 mas
Reflective 3W (0.9", 0.45", 0.6")
The reflective coating is not uniform where the white patterns are seen in the figure below. These regions can only be used for estimating the intensity of the spectral features.
Reflective 4 (0.3", 0.15", 0.1", 0.225")
The regions specified with green boxes are suitable for observations (other regions have damages in the surface coating and the efficiency is low).
The reflective coating is not uniform where the white patterns are seen in the figure below. These regions can only be used for estimating the intensity of the spectral features.
