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At least 685 records · Page 38

Diagnosis of separated flow regions on wind-tunnel models using an infrared camera

A novel technique utilizing an infrared-sensitive imaging camera has been used to determine the location of three-dimensional (3-D) separated flow regions on an inclined 5 deg semiangle fiberglass cone. The results illustrate that there is a change in the contrast of the infrared (IR) signature on the cone surface corresponding with the location where the skin-friction lines merge toward lines of 3-D separation. This technique should offer a convenient means for locating separated flow regions on wind-tunnel models while obtaining simultaneous force, skin-friction, and pressure data.

Bandettini, A.↗

800 x 800 charge-coupled device /CCD/ camera for the Galileo Jupiter Orbiter mission

During January 1982 the NASA space transportation system will launch a Galileo spacecraft composed of an orbiting bus and an atmospheric entry probe to arrive at the planet Jupiter in July 1985. A prime element of the orbiter's scientific instrument payload will be a new generation slow-scan planetary imaging system based on a newly developed 800 x 800 charge-coupled device (CCD) image sensor. Following Jupiter orbit insertion, the single, narrow-angle, CCD camera, designated the Solid State Imaging (SSI) Subsystem, will operate for 20 months as the orbiter makes repeated encounters with Jupiter and its Galilean Satellites. During this period the SSI will acquire 40,000 images of Jupiter's atmosphere and the surfaces of the Galilean Satellites. This paper describes the SSI, its operational modes, and science objectives.

Clary, M. C.↗

Outer planet investigations using a CCD camera system

Problems related to analog noise, data transfer from the camera buffer to the storage computer, and loss of sensitivity of a two dimensional charge coupled device imaging system are reported. To calibrate the CCD system, calibrated UBV pinhole scans of the Saturn disk were obtained with a photoelectric area scanning photometer. Atmospheric point spread functions were also obtained. The UBV observations and models of the Saturn atmosphere are analyzed.

Price, M. J.↗

Schwarzschild camera

The fabrication procedures for the primary and secondary mirrors for a Schwarzschild camera are summarized. The achieved wave front for the telescope was 1/2 wave at .63 microns. Interferograms of the two mirrors as a system are given and the mounting procedures are outlined.

Source record↗

Preliminary results from a single-photon imaging X-ray charge coupled device /CCD/ camera

A CCD camera is described which has been designed for single-photon X-ray imaging in the 1-10 keV energy range. Preliminary results are presented from the front-side illuminated Fairchild CCD 211, which has been shown to image well at 3 keV. The problem of charge-spreading above 4 keV is discussed by analogy with a similar problem at infrared wavelengths. The total system noise is discussed and compared with values obtained by other CCD users.

Griffiths, R. E.↗

Metric camera experiment

A test of the mapping capabilities of high resolution space photography taken at the resolution limit of image motion on large film format is planned. The metric camera system and its planned operation are described.

Reynolds, M.↗

Very wide field camera

The study of galactic and faint extragalactic extended sources and peculiar ultraviolet objects by a very wide field of view camera, operated in the ultraviolet photometric and spectrometric modes is discussed. The photometric mode is direct photography through filters for observation of the following sources: (1) large scale distribution of ultraviolet radiation in the Milky Way; (2) diffusion of the galactic light above the galactic plane and in front of the large absorbing clouds; (3) the optical emission of the interstellar matter; (4) stars, and starlike objects with diameters less than 3 arc minutes. In the spectrometric mode (nebular spectrograph) the light from the center of the photometric field is concentrated on a slit covering 10 degrees by 10 arc minutes on the sky.

Courtes, G.↗

High-speed motion picture camera experiments of cavitation in dynamically loaded journal bearings

A high-speed camera was used to investigate cavitation in dynamically loaded journal bearings. The length-diameter ratio of the bearing, the speeds of the shaft and bearing, the surface material of the shaft, and the static and dynamic eccentricity of the bearing were varied. The results reveal not only the appearance of gas cavitation, but also the development of previously unsuspected vapor cavitation. It was found that gas cavitation increases with time until, after many hundreds of pressure cycles, there is a constant amount of gas kept in the cavitation zone of the bearing. The gas can have pressures of many times the atmospheric pressure. Vapor cavitation bubbles, on the other hand, collapse at pressures lower than the atmospheric pressure and cannot be transported through a high-pressure zone, nor does the amount of vapor cavitation in a bearing increase with time. Analysis is given to support the experimental findings for both gas and vapor cavitation.

Jacobson, B. O.↗

Radiometric performance of the Voyager cameras

The Voyager Imaging Experiment provided high-quality data of Jupiter and the Galilean satellites with the two flyby trajectories in March and July of 1979. Moderately accurate radiometric measurements have been made using these data. This paper evaluates the radiometric results and describes the inflight and ground geometric and radiometric correction factors. The radiometric quantities of intensity I and geometric albedo I/F are derived, and scaling factors for each of the filters are tabulated for correcting the 'calibrated' data from the Image Processing Laboratory at JPL. In addition, the key characteristics of both Voyager I and Voyager 2 cameras are tabulated.

Danielson, G. E.↗

On the linearity of the SWP camera of the international ultraviolet explorer /IUE/ - A correction algorithm

An algorithm is presented for correcting IUE low resolution spectral images obtained with the SWP camera for some of the non-linearity effects reported by Bohlin et al. (1980). The non-linearity problem, which affects SWP images processed at Goddard Space Flight Center in the period May 22, 1978 to July 7, 1979 and at VILSPA in the period June 14, 1978 to August 6, 1979, was essentially due to the use of an Intensity Transfer Function (ITF) that erroneously included a blank image in the 20 percent exposure level. The correction algorithm described here was adopted by the three IUE Agencies in November 1979 as being suitable for most IUE users. It has the advantages to be applicable to any kind of low resolution SWP spectra, to introduce errors which are usually less than the intrinsic photometric errors, and to be of simple application. The results obtained by applying the method to a representative set of spectra of both point and extended sources are reported. In addition, a new evaluation of linearity and reproducibility of the SWP spectral data is provided, based on the improved ITF.

Holm, A.↗

Modulated Multiple Slit Camera for improved localization of gamma ray bursts

An instrument is described in which a cylindrical modulation collimator is added to one half of a Multiple Slit Camera (MSC) coded-aperture imaging system. The instrument provides gamma-ray burst positions from a single spacecraft that are as precise as the best positions from the long-baseline network of interplanetary spacecraft. The determination of fine positions is described, and the fine-position capability is shown to operate over about two-thirds of the MSC's nearly all-sky field of view. It is noted that the addition of the modulation collimator only slightly reduces the system's sensitivity and can improve the location precision for gamma-ray bursts and slower hard-X-ray transients to about 0.1 sq arcmin.

Gorenstein, P.↗

An example of the performance of the space telescope planetary camera

A ground-based CCD picture of the relatively local dwarf irregular galaxy Sextans B is used to simulate a Space Telescope Planetary Camera image of a similar galaxy at the distance of the Virgo cluster. The gains to be had with the Space Telescope are discussed graphically.

Hoessel, J. G.↗

High-speed motion picture camera experiments of cavitation in dynamically loaded journal bearings

A high-speed camera was used to investigate cavitation in dynamically loaded journal bearings. The length-diameter ratio of the bearing, the speeds of the shaft and bearing, the surface material of the shaft, and the static and dynamic eccentricity of the bearing were varied. The results reveal not only the appearance of gas cavitation, but also the development of previously unsuspected vapor cavitation. It was found that gas cavitation increases with time until, after many hundreds of pressure cycles, there is a constant amount of gas kept in the cavitation zone of the bearing. The gas can have pressures of many times the atmospheric pressure. Vapor cavitation bubbles, on the other hand, collapse at pressures lower than the atmospheric pressure and cannot be transported through a high-pressure zone, nor does the amount of vapor cavitation in a bearing increase with time. Analysis is given to support the experimental findings for both gas and vapor cavitation. Previously announced in STAR as N82-20543

Hamrock, B. J.↗

Spas color camera

The procedures to be followed in assessing the performance of the MOS color camera are defined. Aspects considered include: horizontal and vertical resolution; value of the video signal; gray scale rendition; environmental (vibration and temperature) tests; signal to noise ratios; and white balance correction.

Toffales, C.↗

Image dissector camera system study

Various aspects of a rendezvous and docking system using an image dissector detector as compared to a GaAs detector were discussed. Investigation into a gimbled scanning system is also covered and the measured video response curves from the image dissector camera are presented. Rendezvous will occur at ranges greater than 100 meters. The maximum range considered was 1000 meters. During docking, the range, range-rate, angle, and angle-rate to each reflector on the satellite must be measured. Docking range will be from 3 to 100 meters. The system consists of a CW laser diode transmitter and an image dissector receiver. The transmitter beam is amplitude modulated with three sine wave tones for ranging. The beam is coaxially combined with the receiver beam. Mechanical deflection of the transmitter beam, + or - 10 degrees in both X and Y, can be accomplished before or after it is combined with the receiver beam. The receiver will have a field-of-view (FOV) of 20 degrees and an instantaneous field-of-view (IFOV) of two milliradians (mrad) and will be electronically scanned in the image dissector. The increase in performance obtained from the GaAs photocathode is not needed to meet the present performance requirements.

Howell, L.↗

In-situ measurements of alloy oxidation/corrosion/erosion using a video camera and proximity sensor with microcomputer control

Two noncontacting and nondestructive, remotely controlled methods of measuring the progress of oxidation/corrosion/erosion of metal alloys, exposed to flame test conditions, are described. The external diameter of a sample under test in a flame was measured by a video camera width measurement system. An eddy current proximity probe system, for measurements outside of the flame, was also developed and tested. The two techniques were applied to the measurement of the oxidation of 304 stainless steel at 910 C using a Mach 0.3 flame. The eddy current probe system yielded a recession rate of 0.41 mils diameter loss per hour and the video system gave 0.27.

Deadmore, D. L.↗