Change page style:
T-ReCS contains 7 slit masks for spectroscopy, plus an "open" mask and an occulting bar for imaging mode. The slit widths are chosen to match the lambda/D and 2*lambda/D conditions at the upper end of the 10 and 20 µm wavelength bands, plus the lambda/D condition at three additional wavelengths in the 10 µm band. The lambda/D slits will generally provide the best spectral resolution in good seeing; the 2*lambda/D slits may be better in poor seeing or for fainter sources.
T-ReCS contains three diffraction gratings and an optical flat mounted on a rotating turret. Each diffraction grating is used in first order.
T-ReCS contains up to 20 filters mounted in two wheels. This page describes the current set of filters.
T-ReCS contains three entrance windows that are interchangeable in real time; the control software selects the window that is best for the specific observation and conditions.
T-ReCS contains the same detector as Michelle . Some basic characteristics of the detectors are shown in the table below:
Basic characteristics of T-ReCS's imaging mode
T-ReCS is capable of imaging in the 8–26 micron range as follows:
- Broad-band (N, Q) and Narrow-band Filter Imaging
- Pixel size = 0.09" (fixed)
- Field of view = 28.8"×21.6"
- Number of filters: currently 20, capacity for 24
- Occulting bar available for imaging (2" wide)
The principal T-ReCS imaging modes, plus the typical settings of five instrument components in each mode, are listed in the following table.
The following table gives wavelength ranges of the order-sorting filters in NIRI that are used with the grisms. The Gemini identification number for each filter is recorded in data file headers.
The available slits are shown in the following table. The slit widths are given in pixels and arcsec projected on the sky. The spectral resolution is lower in a wider slit (see the grism table), even for point sources since under most atmospheric conditions the seeing wings of pointlike objects fill the wider slits. Note that for each f/6 slit width, 2 slits are available, one of which is offset from the optical axis and causes the spectrum to be shifted to shorter wavelengths on the array. Note also that the f/32 10 pixel wide slit and the f/6 2 pixel wide slit are the same slit.