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Wyman, C. L.

Publications and source records attributed to Wyman, C. L..

At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Correspondence between AXAF TMA X-ray performance and models based upon mechanical and visible light measurements

The AXAF Technology Mirror Assembly (TMA) was characterized prior to X-ray testing by properties measured mechanically or with visible light; these include alignment offsets, roundness and global-axial-slope errors, axial-figure errors with characteristic lengths greater than about five mm, and surface roughness with scale lengths between about 0.005 and 0.5 mm. The X-ray data of Schwartz et al. (1985) are compared with predictions based upon the mechanical and visible light measurements.

Van Speybroeck, L.↗
NASA NTRS1984

The AXAF technology program: The optical flats tests

The results of a technology program aimed at determining the limits of surface polishing for reflecting X-ray telescopes is presented. This program is part of the major task of developing the Advanced X-ray Astrophysical Facility (AXAF). By studying the optical properties of state-of-the-art polished flat surfaces, conclusions were drawn as to the potential capability of AXAF. Surface microtopography of the flats as well as their figure are studied by X-ray, visual, and mechanical techniques. These techniques and their results are described. The employed polishing techniques are more than adequate for the specifications of the AXAF mirrors.

Williams, A. C.↗
NASA NTRS1984

The Advanced X-Ray Astrophysics Facility

The advanced X-Ray Astrophysics Facility (AXAF) will be a free-flying observatory for high-quality observations and research in the X-ray spectrum. AXAF is planned to be launched in 1991 by the Shuttle and maintained in-orbit over a period of 15 years. This paper presents a summary of the AXAF program and describes several possible configurations which resulted from Phase A studies.

Dailey, C. C.↗
NASA NTRS1984

The National Symposium and Workshop on Optical Platforms, Huntsville, AL, June 12-14, 1984, Proceedings

The present conference is concerned with space-based observatories (including future systems), interplanetary observation platforms, Space Station optical utilization, orbital earth viewing systems, and Spacelab's use as an observations platform. Attention is given to the pointing system for the Space Telescope, the Advanced X-ray Astrophysics Facility, the conceptual definition of the Space IR Telescope Facility's spacecraft, satellite servicing in light of the Solar Maximum Repair Mission, a large deployable reflector telescope concept, moon-based astronomical observatories, Space Station-based remote sensing of the earth, optical systems is geosynchronous orbit, multispectral linear array detector technology, Spacelab-based space plasma and materials processing investigations, and space construction technology for large space observatories. Also discussed are military optical platforms for sea, land and air stationing.

Wyman, C. L.↗
NASA NTRS1984

AXAF - A major spaceborne X-ray observatory

Attention is given to the design configuration and performance requirements of the Advanced X-ray Astrophysics Facility, as established by Phase A study results, noting the conceptual apprach to instrument accommodation by means of a focal plane assembly. Conceptually, the various instruments incorporated are modular in design, so that they may be replaced in orbit using standard interfaces. The instruments in question are high and moderate resolution imagers, a high resolution dispersive spectrometer, a moderate resolution spectrometer, and a focal plane polarimeter.

Wyman, C. L.↗
NASA NTRS1979

An ultraviolet polarimeter for the Solar Maximum Mission

The Solar Maximum Mission experiment contingency will include one instrument originally designed and built for OSO-8. The engineering model of the OSO-8 High Resolution Spectrometer has been rebuilt to make it lightworthy and to encompass several new functions, including solar ultraviolet polarimetry. The rebuilt package is designated as the High Resolution Ultraviolet Spectrometer/Polarimeter. The device that enables polarimetry is a dual channel rotating waveplate system. The waveplates are magnesium fluoride and will allow measurements to be made ranging from the Lyman alpha line to near visible ultraviolet. One wavelength channel will use the polarization characteristics of the spectrometer diffraction grating as the analyzer. The second channel has a built-in four-mirror polarizer. This paper describes the polarimeter design, operation, and calibration.

Calvert, J.↗
NASA NTRS1979

Space optics; Proceedings of the Seminar, Huntsville, Ala., May 22-24, 1979

The seminar focused on infrared systems, the space telescope, new design for space astronomy, future earth resources systems, and planetary systems. Papers were presented on infrared astronomy satellite, infrared telescope on Spacelab 2, design alternatives for the Shuttle Infrared Telescope Facility, Spacelab 2 infrared telescope cryogenic system, geometrical theory of diffraction and telescope stray-light analysis, Space Telescope scientific instruments, faint-object spectrograph for the Space Telescope, light scattering from multilayer optics, bidirectional reflectance distribution function measurements of stray light suppression coatings for the Space Telescope, optical fabrication of a 60-in. mirror, interferogram analysis for space optics, nuclear-pumped lasers for space application, geophysical fluid flow experiment, coherent rays for optical astronomy in space, optical system with fiber-optical elements, and Pioneer-Venus solar flux radiometer.

Wyman, C. L.↗
NASA NTRS1979

Influence of alignment and surface defects on the performance of X-ray telescopes

The effects of misalignment and surface deformations on the image quality of a grazing incidence telescope with six nested subsystems are investigated. The axial rms-spot size serves as a measure for the image quality. The surface deformations are simulated by ellipsoidal and sinusoidal deviations from the ideal surface. Misalignments are tilts, decenters, and despaces of the individual elements. The effects of each type of defect are analyzed in a single two-element system. The full nested system is then analyzed in the presence of all possible defects on all 12 elements, whereby the magnitude of the defects is randomized within a given upper limit.

Korsch, D.↗
NASA NTRS1979

Optical systems engineering - A tutorial

The paper examines the use of the systems engineering approach in the design of optical systems, noting that the use of such an approach which involves an integrated interdisciplinary approach to the development of systems is most appropriate for optics. It is shown that the high precision character of optics leads to complex and subtle effects on optical system performance, resulting from structural, thermal dynamical, control system, and manufacturing and assembly considerations. Attention is given to communication problems that often occur among users and optical engineers due to the unique factors of optical systems. It is concluded that it is essential that the optics community provide leadership to resolve communication problems and fully formalize the field of optical systems engineering.

Wyman, C. L.↗
NASA NTRS1978

System for the measurement of ultra-low stray light levels

An apparatus is described for measuring the effectiveness of stray light suppression light shields and baffle arrangements used in optical space experiments and large space telescopes. The light shield and baffle arrangement and a telescope model are contained in a vacuum chamber. A source of short, high-powered light energy illuminates portions of the light shield and baffle arrangement and reflects a portion of same to a photomultiplier tube by virtue of multipath scattering. The resulting signal is transferred to time-channel electronics timed by the firing of the high energy light source allowing time discrimination of the signal thereby enabling the light scattered and suppressed by the model to be distinguished from the walls and holders around the apparatus.

Wyman, C. L.↗
NASA NTRS1975

Analysis and experimental measurement of straylight suppression systems for the large space telescope

A computer program for straylight suppression system design and analysis was developed to analyze various proposed LST straylight suppression systems. Simultaneously, experimental measurements are being made on a simplified LST straylight suppression system in a unique facility. The experimental measurements are being used to verify and improve the computer program. The facility represents the state-of-the-art in straylight suppression measurements, and transmission factors of 10 to the minus 12th power have been measured.

Wyman, C. L.↗
NASA NTRS1974

Strain gauge ambiguity sensor for segmented mirror active optical system

A system is described to measure alignment between interfacing edges of mirror segments positioned to form a segmented mirror surface. It serves as a gauge having a bending beam with four piezoresistive elements coupled across the interfaces of the edges of adjacent mirror segments. The bending beam has a first position corresponding to alignment of the edges of adjacent mirror segments, and it is bendable from the first position in a direction and to a degree dependent upon the relative misalignment between the edges of adjacent mirror segments to correspondingly vary the resistance of the strain guage. A source of power and an amplifier are connected in circuit with the strain gauge whereby the output of the amplifier varies according to the misalignment of the edges of adjacent mirror segments.

Wyman, C. L.↗
NASA NTRS1974

Aplanatic two-mirror telescopes: A systematic study. I - Cassegrainian configuration

A systematic performance analysis of aplanatic Cassegrainian telescopes has been accomplished by means of a ray trace program. The results indicate that the available field angle for a given geometric spot size is, to a very close approximation, a function of the relative back focal distance only. Image curvatures, as computed by third-order theory and by the ray trace program, were found to be in very close agreement. Image curvature is plotted as a function of the ray height ratio for a wide range of secondary magnification.

Wyman, C. L.↗
NASA NTRS1974

A systematic study of focal ratio and effects of optical misalignment for LST

Possible large space telescope geometries are studied to determine performance and the effects of misalignments. The results are displayed parametrically as a function of relative back focal distance (RBFD). As RBFD increases, a larger high resolution field is obtained, and misalignment effects become less severe.

Wyman, C. L.↗