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NIRI Filter Color Transformations

NIRI Filter Color Transformations

The Kprime and Kshort filters can be related to the standard "Mauna Kea" K filter via the following transformations:

    Kshort = K + 0.002 + 0.026(J-K)

    Kprime = K + 0.22(H-K)

The colors are those measured on the Mauna Kea filter system.

Optomechanical Layout

NIRI is an near-IR imager/spectrometer operating over the 1 to 5um wavelength regime. The instrument is cryogenic and is cooled by two Leybold closed-cycle cooler units to an IR array operating temperature of around 30-35K. All optical elements inside the NIRI cryostat are cooled and, in general, will reach operating temperatures of around 60 to 80K. Since NIRI is cryogenic, the cryostat is pumped and cryo-cooled to a pressure better than 10^-5 torr.

The optical chain from entrance window to IR detector is as follows:

Frenetic growth of supermassive black holes in the early universe

Mid-IR Astrometry

Mid-IR observing programmes would often benefit from absolute astrometry with subarcsecond accuracy, for example for comparing mid-IR images of galaxy nuclei or star-forming regions with images at other wavelengths. In this page we guide the user through the steps necessary to set up accurate absolute astrometry in the OT. The procedure at mid-IR wavelengths differs from that used in the optical because of low probability that two stars close enough to use the same guide star will be both bright at 10 or 20 microns.


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