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At least 109 records · Page 6

The use of photographic methods in contrast enhancement of ERTS-1 images

The contrast of ERTS 70mm positive images can be enhanced to varying degrees by rephotographing the images with different types of negative films, and by overdeveloping the films with different developers. A combination of high contrast copy film (Kodak 5069) and a high energy developer (Kodak D-11) yields high contrast. Still greater contrast may be otbained by using a film of higher contrast capability and a developer of higher energy capability. Contrast can also be enhanced in the printing process with the use of highcontrast photographic papers, or with the use of polycontrast photographic paper and filters. Contrast enhancement by photocopying delineates topographic boundaries and may aid in the objective measurement of topographic parameters.

Harris, L. F.↗

Photographic photometry of variable stars

Photographic methods of determining stellar magnitude and measuring brightness of variable stars on negatives include the photoelectric method and the contascope. Calibration curves are usually plotted by the UBV method. Magnitudes of comparison stars can be determined from photographs.

Kholopov, P. N.↗

High spatial resolution photographs of the sun in L alpha radiation.

Photographs of the sun in predominantly L alpha radiation (centered at 1215.67 A) with 3-sec spatial resolution were taken from an Aerobee rocket shortly after fourth contact by the moon on the eclipse day of July 10, 1972. This preliminary reporting of the results describes the instrument and shows two of the photographs taken. The supergranulation is manifest, and active regions and filaments are well resolved over the entire disk. Densitometer traces across the disk are presented, giving the flux incident on the earth from active regions, cell boundaries, and filaments.

Prinz, D. K.↗

Photographic observations of the occultation of Beta Scorpii by Jupiter.

The occultation of the multiple star Beta Scorpii by Jupiter was observed visually and photographically from the Bosscha Observatory in Lembang (Java), Indonesia, on May 13, 1971. The photographs recorded the dimming of the stars as the light was differentially refracted by the Jovian atmosphere, and gave support to a scale height much greater than 8 and more nearly 30 km. In addition, during the ingress of Beta Scorpii, flashes up to 1 second long were observed visually, occurring at irregular intervals, spaced by 2-8 seconds, over a total period of 7 minutes. Measurements of the position of the brightest component of Beta Scorpii during ingress shows refraction of approximately 1.4 sec before becoming unobservable.

Larson, S. M.↗

Skylab 2: Photographic index and scene identification

A quick reference guide to the photographic imagery obtained on Skylab 2 is presented. Place names and descriptors used give sufficient information to identify frames for discussion purposes and are not intended to be used for ground nadir or geographic coverage purposes. The photographs are further identified with respect to the type of camera used in taking the pictures.

Underwood, R. W.↗

Photographic observations of the occulation of Beta Scorpii by Jupiter

The occultation of the multiple star Beta Scorpii by Jupiter was observed visually and photographically from the Bosscha Observatory in Lembang (Java), Indonesia, on May 13, 1971. The photographs recorded the dimming of the stars as the light was differentially refracted by the Jovian atmosphere, and gave support to a scale height much greater than 8 and more nearly 30 km. In addition, during the ingress of Beta Scorpii, flashes up to 1 second long were observed visually (while guiding in the reflex device of the camera) that occurred irregular intervals, spaced by 2-8 seconds, over a total period of 7 minutes. Measurements of the position of the brightest component of Beta Scorpii during ingress shows refraction of approximately 1.4 sec before becoming unobservable.

Larson, S. M.↗

Cosmic-ray cascades photographed in scintillator

Light produced by nuclear-electromagnetic cascades in a plastic scintillator can be photographed, and the resulting images on film used to measure both the energy content of the cascades and also the positions at which the cascades passed through the scintillator. The energy content of a cascade can be measured to 20% and its position determined to plus or minus 0.8 cm in each scintillator. Techniques for photographing the cascades and analyzing the film are described. Sample data are presented and discussed.

Barrowes, S. C.↗

Evaluation of ERTS-1 image sensor spatial resolution in photographic form

The author has identified the following significant results. The digital Optical Transfer Function (OTF) measurements showed the following: (1) there are no significant differences in optical performance, in terms of OTF, among all four bands of the multispectral scanner, (2) no substantial changes in the OTF's of bands 4, 5, and 6 during the period November 1972 to May 1973, and (3) comparison between the photographic and digital (CCT) two-dimensional OTF's indicated a strong asymmetry in the photographic product OTF between the MSS scan direction and across scan direction. The coherent light Fourier analysis program showed the following: (1) for agricultural areas, bands 5 and 7 of the MSS are superior in terms of image definition, and therefore mapping and acreage estimation, (2) amplitude modulation in imagery from MSS bands 4 and 5 is between 65 to 90 percent of that in corresponding bands of Apollo 9 imagery (SO65), and (3) MSS band 5 imagery has a ground resolution between 55 to 75 percent of that exhibited in the corresponding band of Apollo 9 imagery (SO65).

Slater, P. N.↗

Visual and photographic white light flare observations of 4 July 1974

Visual impressions and a photograph of an intense white-light flare are presented. A densitometer trace across the July 4, 1974, flare showing relative intensity of the white-light flare, photosphere, and umbra is also shown. A second white-light flare is suspected on a photograph taken 4-3/4 hr later. Both flares coincide in time with major H alpha-flare activity.

Feibelman, W. A.↗

Apollo-Soyuz test project photographic film processing and sensitometric summary

The Photographic Technology Division at the NASA Lyndon B. Johnson Space Center processed original photographic films exposed in flight during the Apollo Soyuz Test Project (ASTP). Integrated with processing of the original films were strict sensitometric controls and certification procedures established prior to the flight. Information relative to the processing of the 54 rolls of original ASTP flight film and sensitometric data pertinent to each of these rolls of film is presented.

Lockwood, H. E.↗

Lineaments on Skylab photographs: Detection, mapping, and hydrologic significance in central Tennessee

An investigation was carried out to determine the feasibility of mapping lineaments on SKYLAB photographs of central Tennessee and to determine the hydrologic significance of these lineaments, particularly as concerns the occurrence and productivity of ground water. Sixty-nine percent more lineaments were found on SKYLAB photographs by stereo viewing than by projection viewing, but longer lineaments were detected by projection viewing. Most SKYLAB lineaments consisted of topographic depressions and they followed or paralleled the streams. The remainder were found by vegetation alinements and the straight sides of ridges. Test drilling showed that the median yield of wells located on SKYLAB lineaments were about six times the median yield of wells located by random drilling. The best single detection method, in terms of potential savings, was stereo viewing. Larger savings might be achieved by locating wells on lineaments detected by both stereo viewing and projection.

Moore, G. K.↗

Ground cover estimated from aerial photographs

Estimates of per cent ground cover made by ground observers were compared with independent estimates made on the basis of low-altitude (640-1219 m) aerial photographs of the same fields. Standard statistical simple correlation and linear regression analyses revealed a high correlation between the two estimation methods. In crops such as grain, sorghum, corn, and forage sorghum, in which the broadest part of the leaf canopy is near the top of the plant, there was a tendency to overestimate the per cent ground cover from aerial photographs.

Gerbermann, A. H.↗

Gemini photographs of the world: A complete index

The most authoritative catalogs of photographs of all Gemini missions are assembled. Included for all photographs are JSC (Johnson Space Center) identification number, percent cloud cover, geographical area in sight, and miscellaneous information. In addition, details are given on cameras, filters, films, and other technical details.

Giddings, L. E.↗

The astrometric binary Mu Cassiopeiae - Photographically almost resolved

Photographic observations of the Population II subdwarf astrometric binary Mu Cas are described which almost resolve the components and permit an estimate of their magnitudes and separation. Red- and blue-light photographs of the system were taken during an observing period when the component separation was maximum. The separation of the two components is estimated to be about 1.5 arcsec, position angles of about 194 and 201 deg are determined for the two years of the observing period, and the apparent magnitude of the faint companion is found to be approximately 10.

Feibelman, W. A.↗

Image processing of galaxy photographs

New computer techniques for analyzing and processing photographic images of galaxies are presented, with interesting scientific findings gleaned from the processed photographic data. Discovery and enhancement of very faint and low-contrast nebulous features, improved resolution of near-limit detail in nebulous and stellar images, and relative colors of a group of nebulosities in the field are attained by the methods. Digital algorithms, nonlinear pattern-recognition filters, linear convolution filters, plate averaging and contrast enhancement techniques, and an atmospheric deconvolution technique are described. New detail is revealed in images of NGC 7331, Stephan's Quintet, Seyfert's Sextet, and the jet in M87, via processes of addition of plates, star removal, contrast enhancement, standard deviation filtering, and computer ratioing to bring out qualitative color differences.

Arp, H.↗

Photographic coronagraph, Skylab particulate experiment T025

A photographic coronagraph, built to monitor Skylab's extravehicular contamination, is described. This versatile instrument was used to observe the earth's vertical aerosol distribution and Comet Kohoutek (1973f) near perihelion. Although originally designed for deployment from the solar airlock, the instrument was modified for EVA operation when the airlock was rendered unusable. The results of the observations made in four EVA's were almost completely ruined by the failure of a Skylab operational camera used with the coronagraph. Nevertheless, an aerosol layer at 48 km was discovered in the southern hemisphere from the few useful photographs.

Giovane, F.↗

Near earth photographs from the Apollo missions and the Apollo-Soyuz test project, part 4

Apollo Erath Photographs Index - Maps Apollo Mission 9 Apollo 9 frames AS9-19-2989 and 2990, instead of beginning south of Corpus Christi and running north (as shown on page 11of the Apollo Earth Photographs Index Maps document) begins south of Houston and point southward toward Corpus Christi. Because of this the framing indicated on page 11 is reversed.

L. E. Giddings↗

Red and photographic infrared linear combinations for monitoring vegetation

In situ collected spectrometer data were used to evaluate and quantify the relationships between various linear combinations of red and photographic infrared radiances and experimental plot biomass, leaf water content, and chlorophyll content. The radiance variables evaluated included the red and photographic infrared (IR) radiance and the linear combinations of the IR/red ratio, the square root of th IR/red difference, the vegetation index, and the transformed vegetation index. In addition, the corresponding green and red linear combinations were evaluated for comparative purposes. Three data sets were used from June, September, and October sampling periods. Regression analysis showed the increase utility of the IR and red linear combinations vis-a-vis the same green and red linear combinations. The red and IR linear combinations had 7% and 14% greater regression significance than the green and red linear combinations for the June and September sampling periods, respectively. The VI, TVI, and square root of the IR/red ration were the most significant followed closely by the IR/red ratio. Less than 6% difference separated the highest and lowest of these four IR and red linear combinations. The use of these linear combinations was shown to be sensitive primarily to the green leaf area or green leaf biomass.

Tucker, C. J.↗