Switching deckers

This little animation shows the switch between the two slit masks, a.k.a. deckers. One blocks light in the first and third quarter of the slit, the other blocks the second and fourth. The the horizontal spectral order can be seen at the top, the graph below is a vertical cut. The deckers will be used primarily for polarimetry when the two oppositely polarized beams will shine through the respective openings.


The three HAWAII-2RG detectors in their mount, while measuring their relative distance and alignment. This is after their second cool-down in the main cryostat where they seem to perfom adequately.