Automatic computer reduction of astronomical television images
Automatic data reduction system for TV images of star fields acquired from OAO
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Automatic data reduction system for TV images of star fields acquired from OAO
TV data acquisition system for auroral and ionospheric research, noting visual and subvisual detection sensitivity
TV multiplexing and broadband multichannel real time telemetry data transmission without loss between Kennedy Space Center and ground station for computer operation
Low cost TV ground receiving systems for signals transmitted from synchronous satellites, describing reception techniques, manufacturing and performance characteristics
Camera with characteristics of vidicon camera and greater resolution than home TV receiver uses mosaic of phototransistors. Because of low power and small size, camera has many applications. Mosaics can be used as cathode ray tubes and analog-to-digital converters.
Surveyor 3 landed on the moon in April 1967. Part of the spacecraft was returned to earth in November 1969 by the Apollo 12 astronauts. A stripping film containing dust removed from the camera light filter was received for study. The study involved the characterization of the dust; the results of the study are presented.
A sample of cable described as four inches of TV cable, fabric wrapped, which had been exposed to the atmosphere for an unknown period of time, was subjected to extensive chemical analyses for the various components. The fabric was tested using attenuated total reflectance, chloroform extract, aqueous extraction, pyrolysis infrared, and reflectance spectroscopy. The wire insulation was tested using pyrolysis infrared, pyrolysis gas chromatography, differential thermal analysis, attenuated total reflectance subsurface, and tensile tests. Corrosion was also observed in parts of certain wires.
The locations of various parts of the Surveyor camera are presented. Tables were prepared with emphasis on: (1) exterior parts and surfaces that are directly exposed to space, (2) parts that shield others from space radiation, (3) representative or unique materials, and (4) electronic devices that may contain unique or well-characterized materials.
The celescope instrumentation and data analysis system is described, the major problems encountered during orbital operation are summerized, and a few major problems that were anticipated but did not materialize are listed.
An optics study was performed to establish a candidate optical system design for the proposed NASA Mariner Jupiter/Saturn 77 mission. The study was performed over the 6-month period from January through June 1972. The candidate optical system contains both a wide angle (A) and a narrow angle (B) lens. An additional feature is a transfer mirror mechanism that allows image transfer from the B lens to the vidicon initially used for the A lens. This feature adds an operational redundancy to the optical system in allowing for narrow angle viewing if the narrow angle vidicon were to fail. In this failure mode, photography in the wide angle mode would be discontinued. The structure of the candidate system consists mainly of aluminum with substructures of Invar for athermalization. The total optical system weighs (excluding vidicons) approximately 30 pounds and has overall dimensions of 26.6 by 19.5 by 12.3 inches.
An adaptive variable length coding system is presented. Although developed primarily for the proposed Grand Tour missions, many features of this system clearly indicate a much wider applicability. Using sample to sample prediction, the coding system produces output rates within 0.25 bit/picture element (pixel) of the one-dimensional difference entropy for entropy values ranging from 0 to 8 bit/pixel. This is accomplished without the necessity of storing any code words. Performance improvements of 0.5 bit/pixel can be simply achieved by utilizing previous line correlation. A Basic Compressor, using concatenated codes, adapts to rapid changes in source statistics by automatically selecting one of three codes to use for each block of 21 pixels. The system adapts to less frequent, but more dramatic, changes in source statistics by adjusting the mode in which the Basic Compressor operates on a line-to-line basis. Furthermore, the compression system is independent of the quantization requirements of the pulse-code modulation system.
At orbit insertion, the Martian surface was largely obscured by a dust haze with an extinction optical depth that ranged from near unity in the south polar region to probably greater than two over most of the planet. The only features clearly visible were the south polar cap, one dark spot in Nix Olympica, and three dark spots in the Tharsis region. During the third week, the atmosphere began to clear and surface visibility improved, but contrasts remained a fraction of their normal value. Each of the dark spots that apparently protrude through most of the dust-filled atmosphere has a crater or crater complex in its center. The craters apparently were formed by subsidence and resemble terrestrial calderas.
Application of data from the Celescope Catalog of Ultraviolet Observations to various problems of stellar and interstellar astrophysics. These include refinements in the incorporation of line blanketing in theoretical stellar-atmosphere models, variations in the law of interstellar extinction from one region of the sky to another, and selection and identification of various types of peculiar stars for further investigation. In addition, the data were analyzed to determine the photometric and astrometric accuracy of the Celescope equipment.
A TV image of the entire sun while an importance 2N solar flare was in progress was recorded in the extreme ultraviolet (XUV) radiation band 171-630 A and was transmitted to ground from an Aerobee-150 rocket on Nov. 4, 1969 using S-band telemetry. The camera tube was a SEC vidicon, with its fiber optic faceplate coated with an XUV-to-visible conversion layer of p-quaterphenyl. The XUV passband was produced by three 1000-A thick aluminum filters in series together with the platinized reflecting surface of the off-axis paraboloid that imaged the sun. A number of images were recorded with integration times between 1/30 sec and 2 sec. Reconstruction of pictures was enhanced by combining several to reduce the noise.
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In this system, both left and right optical images pass through same set of optical lenses and same TV transmission and receiving systems. Transmitted stereo images are of high quality because differences in image tone and gray scales, disparities in relative focusing and magnification, and nonsimilar distortions produced by electrical and optical imperfections are minimized.
A statistical analysis of propagation characteristics at 12 GHz for the design of a worldwide communication satellite system is reported. High power spaceborne TV transmitter design and the development of a low cost, low noise ground receiver for domestic reception are considered most important for implementation of a TVBS system.