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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Errors induced in the measurement and azimuth directions of morphological features imaged on oblique Lunar Orbiter photographs

Many quantitative lunar studies, e.g., the morphology and dimensions of craters, crater density and distribution, have been performed using oblique Lunar Orbiter photographs. If the inherent change in scale and azimuth direction of features imaged on these photographs are not corrected, the measurement can be in considerable error and the resulting statistical inferences may be invalid. The magnitude of this error is dependent upon: the depression angle of the camera, the flight height of the spacecraft, the focal length of the camera, and the position and orientation of the object on the ground. The errors introduced by using unrectified oblique photographs as though they were vertical photographs are examined for several Lunar Orbiter high resolution NASA LRC Enhancement photographic prints taken at various depression angles.

Siegal, B. S.↗
NASA NTRS1983

Photography and photographic-photometry of the solar aureole

This paper describes procedures for taking solar aureole photographs with conventional small format (35- or 70-mm) cameras and films and discusses photographic-photometry techniques for obtaining accurate solar aureole radiance measurements from these photographs, the measurements being used for retrieving atmospheric aerosol characteristics. The photographic data reduction techniques discussed here include sensitometry, densitometry, off-axis illumination distribution measurement, photogrammetry and photometry relations, etc. Comparison tests show that photographic measurements of the solar aureole radiance agree well with simultaneous photoelectric measurements.

Deepak, A.↗
NASA NTRS1946

Analysis of Spark-Ignition Engine Knock as Seen in Photographs Taken at 200,000 Frames Per Second

A motion picture of the development of knock in a spark-ignition engine is presented, which consists of 20 photographs taken at intervals of 5 microseconds, or at a rate of 200,000 photographs per second, with an equivalent wide-open exposure time of 6.4 microseconds for each photograph. A motion picture of a complete combustion process, including the development of knock, taken at the rate of 40,000 photographs per second is also presented to assist the reader in orienting the photographs of the knock development taken at 200,000 frames per second.

Miller, Cearcy D↗
NASA NTRS2005

Urban forms, physical activity and body mass index: a cross-city examination using ISS Earth Observation photographs

Johnson Space Center has archived thousands of astronauts acquired Earth images. Some spectacular images have been widely used in news media and in k-12 class room, but their potential utilizations in health promotion and disease prevention have relatively untapped. The project uses daytime ISS photographs to define city forms and links them to city or metropolitan level health data in a multicity context. Road connectivity, landuse mix and Shannon's information indices were used in the classification of photographs. In contrast to previous remote-sensing studies, which tend to focus on a single city or a portion of a city, this project utilized photographs of 39 U.S. cities. And in contrast to previous health-promotion studies on the built environment, which tend to rely on survey respondents' responses to evaluate road connectivity or mixed land use for a single study site, the project examined the built environments of multiple cities based on ISS photos. It was found that road connectivity and landuse mix were not statistically significant by themselves, but the composite measure of the Shannon index was significantly associated with physical activity, but not BMI. Consequently, leisure-time physical activity seems to be positively associated with the urban complexity scale. It was also concluded that unless they are planned or designed in advance, photographs taken by astronauts generally are not appropriate for a study of a single-site built environment nor are they appropriate for a study of infectious diseases at a local scale. To link urban built environment with city-wide health indicators, both the traditional nadir view and oblique views should be emphasized in future astronauts' earth observation photographs.

Lin, Ge↗
NASA NTRS1972

Photographic films as remote sensors for measuring albedos of terrestrial surfaces

To test the feasibility of remotely measuring the albedos of terrestrial surfaces from photographic images, an inquiry was carried out at ground level using several representative common surface targets. Problems of making such measurements with a spectrally selective sensor, such as photographic film, have been compared to previous work utilizing silicon cells. Two photographic approaches have been developed: a multispectral method which utilizes two or three photographic images made through conventional multispectral filters and a single shot method which utilizes the broad spectral sensitivity of black and white infrared film. Sensitometry related to the methods substitutes a Log Albedo scale for the conventional Log Exposure for creating characteristic curves. Certain constraints caused by illumination goemetry are discussed.

Pease, S. R.↗
NASA NTRS1971

Exploration of Marine Resources by Photographic Remote Sensing

The interpretation of photographs in oceanographic remote sensing is discussed. The photographs were made from spacecraft with two exceptions. Two photographs were made from aircraft. There were three types of film used to make the photographs: black-and-white, color, and color IR. Black and white photography is well known; it presents pictures in various shades of gray from black to white. Color film presents pictures in color, very nearly as the human eye sees them. Color IR film presents pictures in color also but not as seen by the human eye. Blue becomes much deeper blue, green is suppressed to some extent, and red is recorded beyond the visual range of the human eye, out in the near infrared. The most noticeable effect of the use of color IR film is that leaf materials which are highly reflective in the infrared part of the spectrum are presented as red.

Duntley, S. Q.↗
NASA NTRS1973

A high-speed photographic system for flow visualization in a steam turbine

A photographic system was designed to visualize the moisture flow in a steam turbine. Good performance of the system was verified using dry turbine mockups in which an aerosol spray simulated, in a rough way, the moisture flow in the turbine. Borescopes and fiber-optic light tubes were selected as the general instrumentation approach. High speed motion-picture photographs of the liquid flow over the stator blade surfaces were taken using stroboscopic lighting. Good visualization of the liquid flow was obtained. Still photographs of drops in flight were made using short duration flash sources. Drops with diameters as small as 30 micrometers (0.0012 in.) could be resolved. In addition, motion pictures of a spray of water simulating the spray off the rotor blades and shrouds were taken at normal framing rates. Specially constructed light tubes containing small tungsten-halogen lamps were used. Sixteen millimeter photography was used in all cases. Two potential problems resulting from the two-phase turbine flow (attenuation and scattering of light by the fog present and liquid accumulation on the borescope mirrors) were taken into account in the photographic system design but not evaluated experimentally.

Barna, G. J.↗
NASA NTRS1972

The contributions of Ranger photographs to understanding the geology of the moon

Vidicon photographs returned to earth by Rangers 7, 8, and 9 in 1964 and 1965 were used to study the details of lunar geologic units previously recognized from earth-based telescopic photographs and to make geologic maps at a variety of scales. The photographs from each mission changed continuously in scale as the spacecraft approached impact. The final frames had resolutions some 1,000 times better than the best earthbased photographs. Lunar stratigraphic units mapped at a scale of 1:1,000,000 displayed, at these larger scales, differences in properties and, possibly, in ages, but a clear-cut stratigraphic succession of subunits was not apparent. The plains-forming materials in both terra and mare were divisible into units mainly on the basis of the differences in the total number of superposed craters and in the relative number of craters of various morphologic types.

Trask, N. J.↗
NASA NTRS1974

Determining spacecraft and airplane angular orientation from star photographs

The advantages of determining spacecraft angular orientation from star photographs include the documental nature and objectivity of the photographic image and also the high accuracy of construction of the reference system based on the stars. Use of the method presupposes installation aboard the vehicle of a specialized photographic camera adapted for photographing the stellar sky. From the mathematical viewpoint, the essence of the method amounts to: (1) Certain directions in space are identified and their direction cosines are determined in a specified coordinate system. (2) The direction cosines of these same directions are determined relative to a coordinate system fixed with the vehicle. (3) The sought angular orientation of the vehicle is calculated using the coupling equations between the specified and vehicle-fixed coordinate systems. In principle, vehicle angular orientation can be determined relative to any given reference system.

Elbakyan, K. I.↗
NASA NTRS1975

Analysis of tectonic features in US southwest from Skylab photographs

The author has identified the following significant results. Skylab photographs were utilized to study faults and tectonic lines in selected areas of the U.S. Southwest. Emphasis was on elements of the Texas Zone in the Mojave Desert and the tectonic intersection in southern Nevada. Transverse faults believed to represent the continuation of the Texas Zone were found to be anomalous in strike. This suggests that the Mojave Desert block was rotated counterclockwise as a unit with the Sierra Nevada. Left-lateral strike-slip faults in Lake Mead area are interpreted as elements of the Wasatch tectonic zone; their anomalous trend indicates that the Lake Mead area has rotated clockwise with the Colorado Plateau. A tectonic model relating major fault zones to fragmentation and rotation of crustal blocks was developed. Detailed correlation of the high resolution S190B metric camera photographs with U-2 photographs and geologic maps demonstrates the feasibility of utilizing S190B photographs for the identification of geomorphic features associated with recent and active faults and for the assessment of seismic hazards.

Abdel-Gawad, M.↗
NASA NTRS1986

Black-and-white photographic chemistry: A reference

This work is intended as a reference of black-and-white photographic chemistry. Included is a basic history of the photographic processes and a complete description of all chemicals used, formulas for the development and fixation process, and associated formulas such as cleaners, hardeners, and toners. The work contains a complete glossary of photographic terms, a trouble-shooting section listing causes and effects regarding photographic film and papers, and various conversion charts.

Walker, E. D.↗
NASA NTRS1987

The role of photographic parameters in laser speckle or particle image displacement velocimetry

The parameters involved in obtaining the multiple exposure photographs in the laser speckle velocimetry method (to record the light scattering by the seeding particles) were optimized. The effects of the type, concentration, and dimensions of the tracer, the exposure conditions (time between exposures, exposure time, and number of exposures), and the sensitivity and resolution of the film on the quality of the final results were investigated, photographing an experimental flow behind an impulsively started circular cylinder. The velocity data were acquired by digital processing of Young's fringes, produced by point-by-point scanning of a photographic negative. Using the optimal photographing conditions, the errors involved in the estimation of the fringe angle and spacing were of the order of 1 percent for the spacing and +/1 deg for the fringe orientation. The resulting accuracy in the velocity was of the order of 2-3 percent of the maximum velocity in the field.

Lourenco, L.↗
NASA NTRS1992

Multichannel astrometric photometer and photographic astrometric studies in the regions of Lalande 21185, BD 56 deg 2966, and HR 4784

The parallaxes of stars determined from the multichannel astrometric photometer (MAP) in the regions of Lalande 21185, BD 56 deg 2966, and from photographic plates in the region of BD 56 deg 2966 and the region of HR 4783 and HR 4784 are reported. The parallax determined for Lalande 21185, 395.1 +/-1.0 mas yields what is believed to be the most precise distance modulus (-2.984 +/-0.0055) known for a star other than the sun. The absolute magnitude of Lalande 21185 is found to be 10.474 +/-0.008. No significant evidence of unseen companions is detected. The photographic study of BD 56 deg 2966 indicates that the long-term (65 yr) motion of the star is linear to better than +/-16 mas, while the MAP study indicates that the motion is linear to better than +/-2.5 mas over a period of some 5 yr. The photographically determined parallaxes are compared with those observed with the MAP. The photographically calculated standard errors are found to be in agreement with the standard error of the differences.

Gatewood, George↗
NASA NTRS1993

Cape Photographic Durchmusterung, volume 1

The Cape Photographic Durchmusterung (CPD Gill and Kapteyn 1895-1900) is a photographic survey of southern stars in the declination range -18 to -90 degrees. This volume covers the declination range -18 through -37 degrees. Positions are given for the 1875 equinox. The summary of the positional uncertainties quoted in the third volume of the published catalog gives +/- 0.28 sec (R.A.) +/- 0.044 arcmin (Dec.) for zones -18 to -57 degrees. The probable error of a photographic magnitude as determined by combining results for different magnitudes and weighting proportionately according to the numbers of stars in each class of magnitude is given as +/- 0.055 mag. From an analysis of the taint magnitude limits on the plates discussed in the third volume introduction, the catalog as a whole can be considered complete to photographic magnitude 9.2 but it is stated that it will be found practically complete in or near the Milky Way, to magnitude 9.5.

Source record↗
NASA NTRS1993

Cape Photographic Durchmusterung, volume 2

The Cape Photographic Durchmusterung (CPD, Gill and Kapteyn 1895-1900) is a Photographic survey of southern stars in the declination range -18 to -90 degrees. This volume covers the declination range -53 through -89 degrees. Positions are given for 1875 equinox. The summary of the positional uncertainties quoted in the third volume of the published catalog gives +/- 0.28 sec (R.A.), +/- 0.044 arcmin (Dec.) for zones - 18 to -57 degrees, + 0.157 sec + 0.0764/cos(delta) sec (R.A.), +/- 0.056 arcmin (Dec.) for zones -58 to -85 degrees, +0.157 sec + 0.0353/cos (delta) sec (R.A.), + 0.0127 arcmin (Dec.) for the polar plate where, as explained in the introduction to the third volume, many positions were derived from rectangular coordinates (these are positions reported to 0.1 SCC (R.A.) and 0.001 arcmin (Dec.) in the -86 to -89 degree zones in the catalog). The probable error of a photographic magnitude, as determined by combining results for different magnitudes and weighting proportionately according to the numbers of stars in each class of magnitude, is given as +0.055 mag. From an analysis of the faint magnitude limits on the plates discussed in the third volume introduction, the catalog as a whole can be considered complete to photographic magnitude 9.2, but it is stated that it will be found practically complete, in or near the Milky Way, to magnitude 9.5.

Source record↗
NASA NTRS1993

Cape Photographic Durchmusterung, volume 3

The Cape Photographic Durchmusterung (CPD, Gill and Kapleyn 1895-1900) is a photographic survey of southern stars in the declination range -18 to -90 degrees. This volume covers the declination range -53 through -89 degrees. Positions are given for the 1875 equinox. The summary of the positional uncertainties quoted in the third volume of the published catalog gives +/- 0.28 sec (R.A.), + 0.044 arcmin (Dec.) for zones -18 to -57 degrees, + 0.157 sec + 0.0764/cos(delta) sec (R.A.), +/- 0.056 arcmin (Dec.) for zones -58 to -85 degrees, +0.157 sec + 0.0353/cos(delta) sec (R.A.), +/- 0.0127 arcmin (Dec.) for the polar plate where, as explained in the introduction to the third volume, many positions were derived from rectangular coordinates (these are positions reported to 0.1 sec (R.A.) and 0.001 arcmin (Dec.) in the -86 to -89 degree zones in the catalog). The probable error of a photographic magnitude, as determined by combining results for different magnitudes and weighting proportionately according to the numbers of stars in each class of magnitude, is given as +0.055 mag. From an analysis of the faint magnitude limits on the plates discussed in the third volume introduction, the catalog as a whole can be considered complete to photographic magnitude 9.2, but it is stated that it will be found practically complete, in or near the Milky Way, to magnitude 9.5.

Source record↗
NASA NTRS1993

Ultrahigh resolution photographic films for X-ray/EUV/FUV astronomy

The quest for ultrahigh resolution full-disk images of the sun at soft X-ray/EUV/FUV wavelengths has increased the demand for photographic films with broad spectral sensitivity, high spatial resolution, and wide dynamic range. These requirements were made more stringent by the recent development of multilayer telescopes and coronagraphs capable of operating at normal incidence at soft X-ray/EUV wavelengths. Photographic films are the only detectors now available with the information storage capacity and dynamic range such as is required for recording images of the solar disk and corona simultaneously with sub arc second spatial resolution. During the Stanford/MSFC/LLNL Rocket X-Ray Spectroheliograph and Multi-Spectral Solar Telescope Array (MSSTA) programs, we utilized photographic films to obtain high resolution full-disk images of the sun at selected soft X-ray/EUV/FUV wavelengths. In order to calibrate our instrumentation for quantitative analysis of our solar data and to select the best emulsions and processing conditions for the MSSTA reflight, we recently tested several photographic films. These studies were carried out at the NIST SURF II synchrotron and the Stanford Synchrotron Radiation Laboratory. In this paper, we provide the results of those investigations.

Hoover, Richard B.↗
NASA NTRS1946

The NACA High-Speed Motion-Picture Camera Optical Compensation at 40,000 Photographs Per Second

The principle of operation of the NACA high-speed camera is completely explained. This camera, operating at the rate of 40,000 photographs per second, took the photographs presented in numerous NACA reports concerning combustion, preignition, and knock in the spark-ignition engine. Many design details are presented and discussed, details of an entirely conventional nature are omitted. The inherent aberrations of the camera are discussed and partly evaluated. The focal-plane-shutter effect of the camera is explained. Photographs of the camera are presented. Some high-speed motion pictures of familiar objects -- photoflash bulb, firecrackers, camera shutter -- are reproduced as an illustration of the quality of the photographs taken by the camera.

Miller, Cearcy D↗