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The Pupil Lens Wheel is mounted between Fold Mirrors 1 and 2, close to the plane where the beam passes through the optical bench. By inserting a lens into the beam at this point, an image of the pupil (the telescope secondary mirror M2) is formed on the detector. The wheel has a diameter of ~XXX mm and has four positions.
The Aperture Stop wheel is positioned at the f/16 focal plane just inside the dewar. The 5-position wheel can hold up to 4 stops; the fifth position is reserved for the window imaging lens.
The diagram below shows the T-ReCS optical path from the entrance window to the focal-plane array.
Click on any element for more details of its design and function.
T-ReCS contains 3 off-axis paraboloid mirrors, 3 fixed folding flat mirrors, and 1 additional optical flat on the grating turret. Each mirror is diamond-turned from aluminum alloy with a protected gold coating. The all-reflective optical design ensures that images are confocal across the full wavelength range of the instrument.
To help with the planning of observations, the basic properties of Cohen's 2 primary and 10 secondary standards are listed in the following table. Also listed are a few other stars which are often used as mid-IR standards. Most of the K and N magnitudes are taken from papers I (1992, AJ, 104, 1650) and IV (1995, AJ,
110, 275). In Cohen's system, the 0 magnitude flux density is 655 Jy at K and 35.21 Jy at N.
This page outlines how to reduce images taken with Michelle and T-ReCS using the IRAF tasks in the midir package. Michelle imaging polarimetry reductions are also briefly described. Imaging observations can be reduced almost automatically if the observations were made in good conditions, although some interactive work is often necessary for observations taken under variable conditions.
This file contains most of the night sky OH lines. All the lines belonging to the sequence Delta V=2 to 5, up to V'=9 are included. All the levels with the rotational quantum number J lower than or equal to 16.5 have been considered.>/p>
The different columns contain the following data :
Persson et al. (1998) secondary red standards: