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The Space Telescope Imaging Spectrograph (STIS) was successfully installed into the Hubble Space Telescope (HST) in 1997 February, during the second HST servicing mission, STS-82. STIS is a versatile spectrograph, covering the 115-1000 nm wavelength range in a variety of spectroscopic and imaging modes that take advantage of the angular resolution, unobstructed wavelength coverage, and dark sky offered by the HST. In the months since launch, a number of performance tests and calibrations have been carried out and are continuing. These tests demonstrate that the instrument is performing very well. We present here a synopsis of the results to date.

Image motion compensation by servocontrolled tilt of the secondary mirror is applied in a 40-cm diam f/7.5 Cassegrainian balloon-borne telescope. A tilted-aplanatic configuration is used, i.e., the mirrors are aspherized to render the stabilized image free of third-order coma. A spatial resolution of 2 sec of arc is maintained in the presence of pointing errors up to 10 min of arc. The most important remaining aberrations are third-order astigmatism and fifth-order spherical aberration. For the latter, a general expression is presented that can also be applied to other two-mirror telescopes.

One second of arc pointing accuracy has been achieved by servocontrolling the secondary mirror of a Dall-Kirkham telescope flown in an Aerobee 150 rocket. The primary mirror is weight-relieved, mounted at its nodal line and can resolve 2 arc sec. An objective LiF prism mounted near the focal plane provides a lowresolution far uv spectrum suitable for studying planetary atmospheres. Solar blind photomultiplier tubes with pulse counting electronics provide a dark current background of less than 1 count/sec. Spectra of Venus, Jupiter and eta Ursa Majoris (U Ma) were obtained in a flight from White Sands, New Mexico, on 5 December 1967. Further flights are planned with the recovered package.

Two methods of off-set sun-tracking are described which were developed as part of the balloon-astronomy program of The Johns Hopkins University for daytime observations of the planet Venus. The performance of the system in flight, while subject to oscillations in the suspension system, is discussed.

In this paper, a fuzzy-logic FAM (fuzzy associative memory) matrix classifier is used for the classification (diagnosis) of breast cancer. It is implemented in Mathematica 3.0 and tested on two features (radius and perimeter) from the Wisconsin breast cancer database. The sensitivity of the FAM-matrix classifier is 94.29%, and its specificity is 73.33%.

Like standard discrete artificial neural networks (ANNs), continual neurodynamical systems can be used for the classification and diagnosis of breast cancer. In this paper, a two-feature generalized bidirectional associative memory (GBAM) classifier is formulated in tensorial invariant form. It is implemented in Mathematica 3.0 and tested on two sample features (the radius and perimeter of cell nuclei in fine-needle aspiration slides) from the Wisconsin breast-cancer database. The classification accuracy obtained (86%), together with the invariance of the classification result upon the variation of the dimensions and output form of the neural activation fields, shows the potential classification ability of theoretical classifiers that are directly implemented in computer algebra systems.

The Space Telescope Imaging Spectrograph (STIS) operates from the UV to near IR providing a general purpose, imaging spectroscopic capability. An internal, two mirror relay system corrects the spherical aberration and astigmatism present at the STIS field position. Low and medium resolution imaging spectroscopy is possible throughout the spectral range and over the 25 arcsecond UV and 52 arcsecond visible fields. High resolution echelle spectroscopy capability is also provided in the UV. Target acquisition is accomplished using the STIS cameras, either UV or visible; these cameras may also be used to provide broad band imaging over the complete spectral range or with the small selection of available bandpass filters. A wide selection of slits and apertures permit various combinations of spectral resolution and field size in all modes. On board calibration lamps provide wavelength calibration and flat fielding capability. We report here on the optical performance of STIS as determined during orbital verification.

The STIS instrument was installed into HST in February 1997 during the Servicing Mission 2. It has almost completed checkout and is beginning its science program, and is working well. Several scientific demonstration observations were taken to illustrate some of the range of scientific uses and modes of observation of STIS.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Some calibraton results of the K-Gill propeller vane are discussed. The propellers static and dynamic response were determined. The two propellers show perfect linearity in calibration factor. Starting speed is found less than 0.18 ms-1. Response lengths of the propellers is 2.5 m. effective response in K-Gill configuration is 3.3 m. A new function for propeller response to a drop to zero in wind speed is suggested.

Synopsis The accuracy of some setting methods applicable in two-beam interferometry is investigated with regard to its dependence on the conditions of observation. Photometric methods prove to be the most advantageous. With these, an accuracy of a few thousandths of a wavelength in one setting is attainable under favourable conditions.

On the basis of a simple model for diffraction by the groove, we show that the efficiency of an echelle is high in the Littrow arrangement, but becomes markedly less if the angle of deviation between the incident and the diffracted beams is increased. We also show that the height and width of the spectral image change if the directions of incidence and diffraction are interchanged, but that the efficiency remains the same. In general, the direction of maximum efficiency does not coincide with the blaze direction, defined as the maximum of the envelope of the diffracted-light distribution function. The difference depends on the mode of operation of the spectrograph (scanned or stationary spectrum) and typically changes from a fraction of a degree at high orders in the UV to several degrees at low orders in the IR. Experimental evidence agrees qualitatively with these calculations, but a more refined diffraction model may be needed for a quantitative interpretation.© (1981) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A novel sounding rocket payload consisting of a slitless objective grating spectrograph with no transmission elements in the optical train (or detector) is described. This instrument, called the interstellar medium absorption profile spectrograph (IMAPS), is designed to provide continuous coverage over the wavelength range of 950-1150 A; it has an effective collecting area of about 4 sq cm and can record spectra of pointlike sources at a wavelength resolution of 0.004 A and with a sample interval of 0.002 A. The successful use of this instrument aboard a Black Brant rocket is described.

The High-Resolution Spectrograph (HRS) covers the 105 nm to 320 nm wavelength range at nominal spectral resolutions 103, 104 and 105. It employs one ruled, plane, first-order grating (600 grooves/mm), four holographic, plane, first-order gratings (3600, 4320, 4960 and 6000 grooves/mm), one r/2 echelle (316 grooves/mm) and two ruled, multi-partite, concave cross dispersers (88 and 198 grooves/mm). These gratings are all replicas. The absolute efficiencies of the first-order gratings were measured by the Goddard Space Flight Center (GSFC) before integration into the HRS. The spectral resolution was derived from line-width measurements in the Pt spectrum during pre-flight calibration of the complete instrument at the Ball Aerospace Systems Division (BASD). Relative scattered-light levels were determined from gaseous absorption spectra. In some of the holographic gratings spurious images were observed parallel to the spectra. In the echelle the effective blaze angle in the UV was derived from relative-efficiency measurements and found to be about 62.8°. The spectral resolution and the scattered-light background were measured by the same techniques as above. Ghosts were detected at 0.45 interorder distances. Their relative intensities are less than 0.1% at 150 nm.

The high resolution spectrograph (HRS) for ultraviolet astronomy with the Space Telescope will provide a spectral resolution of approximately 120,000 over a nominal wavelength range of 110-320 nm, together with a spatial resolution of about 0.25 arc seconds. The two detectors will consist of 512-element Digicons with cesium telluride and cesium iodide photocathodes, respectively. Photoelectrons in transit between the photocathodes and the diodes within the Digicons can be deflected in two axes with 12-bit resolution. This feature facilitates a design that emphasizes reliability since (once a hermetic seal is opened in orbit), only two moving parts, a grating carrousel and a shutter, are required for regular operation of the HRS. The instrument will be controlled by a computer in the spacecraft. The scientific objectives of the HRS investigation relate to interstellar matter in our own and nearby galaxies, physical processes of stellar mass loss and mass transfer, chemical abundances, bright quasars and Seyfert galaxy nuclei, and solar system phenomena.

Descriptions of a SISAM-interferometer for space application and of the performance of a Michelson type Fourier transform interferometer are given. The benefits and disadvantages of both instruments in different applications are discussed. The usable wavelength range for the SISAM ranges from 1 to 9 μ (extensible up to 100 μ). The Michelson interferometer is designed for the far infrared beyond 25 μ. The obtained spectral resolution is 0.2 cm−1 and 1 cm−1 respectively. Atmospheric effects on high resolution measurements from balloon or aircraft are discussed.

The interferometer consists of a beamsplitter and two spherical mirrors. Each mirror forms an image of the source on the detector. The transfer function is calculated for a point source and various detectors comparable in size to the diffraction images. The path difference is introduced by moving either one or both of the mirrors. For large detectors, the maximum-permitted path difference is twice the focal tolerance. For small detectors, the usable path difference is somewhat larger but depends on the manner in which the path difference is varied.