A very unique imaging spectopolarimeter for use in the long wave infrared, 8 to 12 microns, is currently being
constructed. The imaging system uses a novel technique first developed at the University of Arizona, which incorporates
channeled spectropolarimetry with a computed tomographic imaging spectrometer (CTIS). The system is especially
noteworthy because it contains no moving parts and operates in a snapshot mode, allowing it to record spectral data as
well as the polarization state of each wavelength band in the spectra from every spatial location in a 2D image in a single
integration period. The paper presents results from the currently constructed longwave infrared snapshot imaging
spectrometer, as well as a description of what will be added to the system to obtain polarization data, and an overview of
the design and operational details of the snapshot imaging spectropolarimeter.
The 1.8 meter Spacewatch telescope and its building on Kitt Peak were dedicated on June 7, 1997 for the purpose of finding previously unknown asteroids and comets. Drift- scanning large areas of sky with a CCD will be done at rates up to 10 times that of the sidereal rate over angles up to 60 degrees of arc along great circles at various orientations. The primary mirror and cell around which the telescope are from the multi-mirror telescope on Mt. Hopkins in Arizona. The telescope's friction drive system allows backlash-free control of its altitude-over-azimuth mount. The mount features bearings of small radii and plenty of motor torque to compensate for wind buffeting. Both incremental and absolute encoders will be used; the absolute encoders will update the position derived from incremental encoders to compensate for the microslipping that is an unavoidable consequence of a friction drive. The control system features commercially produced servo controller cards that are programmed from a user interface program running in a PC under DOS. Realtime operation of the drive is controlled by the interface cards, leaving the PC free to run the display of the position readout and accept keyboard input for the observer without interfering with the drive. It is believed that this design offers the greatest flexibility and accuracy of our search programs.
A moving Ronchi ruling at the focal plane of a telescope has been employed to measure the relative motions of stars with great accuracy. The method has long-term stability and exceptional linearity over a relatively large field-of-view. This measurement technique may prove useful in other applications where such capabilities are required. This paper employs Fourier optics to describe the operation of the device, explore performance at very long and very short periods, and consider ruling profiles and other means of optimizing performance.
The use of a fiber-optic-link CCD-detector Fabry-Perot interferometer (McMillan et al., 1985, 1986, and 1988) to obtain high-accuracy measurements of stellar Doppler shifts at KPNO is described in detail and illustrated with sample data. Particular attention is given to accuracy requirements and techniques for reducing errors, resolution (orders of 50 mA at wavelength 4300 A are separated by 640 mA), CCD sensitivity, observing and data-processing operations, and the control of environmental conditions. Standard-deviation data and statistics on seven solar-type stars are presented in tables, and the time evolution of the radial velocity of Beta Com is shown in a graph.