Orbital science photography. Part F - Correlation of the zero-phase brightness surge /heiligenschein/ with lunar surface roughness
Correlation of zero phase brightness surge - heiligenschein with lunar surface roughness
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Correlation of zero phase brightness surge - heiligenschein with lunar surface roughness
Mathematical modeling and testing of Lunar Orbiter photographic subsystem
Solar Fe XIV 5303 coronal line isolation, using solid Fabry-Perot interferometer as monochromator
Observations made during the Gemini 5, 9, and 10 missions in the context of their relation to ground-based and balloon-based experiments on dim-light phenomena are reported. Zodiacal light is the visible manifestation of dust grains in orbit around the sun. The negatives that were exposed on the Gemini 9 mission were studied by the use of an isodensitracer to produce intensity isophotes. Data on the following factors were obtained: (1) intensity distribution of the zodiacal light, both morning and evening; (2) the height and intensity of the airglow at various geographic positions; and (3) intensity distribution of the Milky Way in the region of the sky near Cygnus. Also, a previously unreported phenomenon was discovered. This phenomenon appeared as an upward extension of the normal 90-kilometer airglow layer. The extension was in the form of wisps or plumes approximately 5 deg wide and extending upward approximately 5 deg. The results obtained from pictures exposed on the Gemini 10 mission were of qualitative or geometrical value only.
The night airglow, which lies in a thin layer 70 to 100 kilometers above the earth, was studied. Although the surface brightness is low when observed through this layer from below, brightness of the airglow is augmented by a factor of approximately 35 when the airglow is viewed tangentially from the vantage point of the Gemini orbit. This augmentation phenomenon is an effective means of synoptic airglow study. The objective was to extend and refine the photographic method. The following techniques were used to achieve this goal: (1) The camera was equipped with a filter to photograph the two prominent line emissions at 5577 and 5893 A; (2) An illuminated camera sight and an aiming camera mount were used in an attempt to reduce the number of blurred photographs; (3) The number of photographs taken and the amount of the earth photographed were as large as possible; and (4) The photograph of the twilight horizon revealed a sunlit dayglow layer.
Eleven photographs were taken of the L sub 4 earth-moon libration region during the Gemini 12 mission. The objective was to investigate the possible existence of clouds or particles of dust orbiting the earth in the L sub 4 region by the use of photographic techniques. No identifiable data were found in the first sequence of five photographs. Star field images could be recognized in two photographs of the second sequence of pictures. A light flare, of unknown source but possibly caused by light refraction from the window of the spacecraft, was recorded in both pictures. A reconstructed star field region (as photographed) is shown Isodensitraces of the two recognizable star fields were made; however, no conclusive results were obtained.
Some simple calculations were made regarding the scattered light phenomenon of a sunlit earth limb. It was assumed that the light was to be scattered by an atmosphere irradiated by a zenith sun. Calculations were made with several different scattering coefficients assignable to various wavelengths of the extended visual region. The dependence of the excess blue-limb elevation was less obviously determined by the scattering angle than was suspected. It is reasonable to surmise that the variation of the values of excess blue-limb elevation originated principally from the red-limb variance, because the form of the blue-limb profiles (at least in their upper part) was more regular than was that of the red-limb profiles.
A data gathering effort on a number of cloud systems is reported. On both manned and unmanned Mercury and Gemini 3 missions, a number of good pictures of cloud systems were obtained. Also, specific experiments were performed by the crewmembers in the Mercury missions. Those experiments involved some of the spectral reflectance characteristics of clouds, land, and water regions of the earth surface as viewed from outside the atmosphere. Pictures obtained on successive revolutions of a Gemini spacecraft were indicative of the changes in and the movements of clouds at approximately 90-min intervals at certain points beneath the track of the spacecraft. A series of such views explain the various meteorological phenomena.
A slate that supported four calibrated color targets was photographed during Gemini 10 mission extravehicular activity to determine if existing outdoor-type color films can reproduce colored objects accurately in the space environment. The experiment resulted in the acquisition of sufficient information to confirm that objects can be photographed in space with good color fidelity by the use of existing materials. Available color film is balanced to the solar spectrum in space, and the effect of ultraviolet energy on film degradation appears to be negligible.
Changes in the red tonal response of Kodak Ektrachrome Infrared Aero 8443 film (EIR) are often incorrectly attributed solely to variations in infrared light reflectance of plant leaves, when the primary influence is a difference in visible light reflectance induced by varying chlorophyll contents. Comparisons are made among aerial photographic images of high- and low-chlorophyll foliage. New growth, foot rot, and boron and chloride nutrient toxicites produce low-chlorophyll foliage, and EIR transparency images of light red or white compared with dark-red images of high-chlorophyll foliage. Deposits of the sooty mold fungus that subsists on the honeydew produced by brown soft scale insects, obscure the citrus leaves' green color. Infected trees appear as black images on EIR film transparencies compared with red images of healthy trees.
Important range-shrub species were identified at acceptable levels of accuracy on large-scale 70 mm color and color infrared aerial photographs. Identification of individual shrubs was significantly higher, however, on color infrared. Photoscales smaller than 1:2400 had limited value except for mature individuals of relatively tall species, and then only if crown margins did not overlap and sharp contrast was evident between the species and background. Larger scale photos were required for low-growing species in dense stands. The crown cover for individual species was estimated from the aerial photos either with a measuring magnifier or a projected-scale micrometer. These crown cover measurements provide techniques for earth-resource analyses when used in conjunction with space and high-altitude remotely procured photos.
A program for determining the feasibility of deriving sea surface wind speeds by remotely sensing ocean surface radiances in the nonglitter regions is discussed. With a knowledge of the duration and geographical extent of the wind field, information about the conventional sea state may be derived. The use of optical techniques for determining sea state has obvious limitations. For example, such means can be used only in daylight and only when a clear path of sight is available between the sensor and the surface. However, sensors and vehicles capable of providing the data needed for such techniques are planned for the near future; therefore, a secondary or backup capability can be provided with little added effort. The information currently being sought regarding white water coverage is also of direct interest to those working with passive microwave systems, the study of energy transfer between winds and ocean currents, the aerial estimation of wind speeds, and many others.
To obtain information about in-place lunar rocks and soil, a closeup stereoscopic camera capable of photographing small scale surface features was used at the Apollo 12 landing site on the Ocean of Storms. Fifteen stereoscopic photograph pairs were obtained. The stereoscopic pairs were of excellent quality and showed the in-place lunar material in detail. The photographs were analyzed and the results compared with the results of the Apollo 12 core sample analysis and other investigations. Significant information about the physical composition and genesis of the lunar soil at the Apollo 12 landing site was obtained. The cohesive soil on the Ocean of Storms probably results from repetitive bombardment of basalt flows by meteorites over long periods of time.
During Apollo 15, fifteen photographs of the moon were taken under Earthshine illumination. These were the first Earthshine photographs taken from lunar orbit. The photographs are of photometric interest, particularly as they involve double reflection of sunlight: by the earth, then the moon, prior to photographic exposure. Certain published data on the mean illumination of the moon by the crescent earth predicted lower exposure values than obtained for each measured area. The apparent albedo values obtained for the floor of the crater Aristarchus were anomalously higher than those obtained for the surrounding maria.
Information on the complete set of Apollo 12 photographs is presented to aid the investigator in the selection and interpretation of photographs. Film type and size, magazine, frame numbers, and identifying remarks are given for the 70-mm coverage, S-158 multispectral coverage, 16-mm coverage, and 35-mm stereo coverage. Background information on mission objectives, photographic equipment, and photographic coverage and quality is included.
A data users' note announces the availability of Apollo 13 pictorial data and aids the investigator in the selection of Apollo 13 photographs for study. This note provides guidance in the interpretation of the photographs. The note includes brief descriptions of the Apollo 13 mission objectives, photographic equipment, and photographic coverage and quality. The National Space Science Data Center (NSSDC) can provide all forms of the photographs described.
The availability of Apollo 14 pictorial data is announced to aid investigators in the selection of Apollo 14 photographs for study. Guidance in the interpretation of the photographs is provided. As background information, the note includes brief descriptions of the Apollo 14 mission objectives, photographic equipment, and photographic coverage and quality. The National Space Science Data Center (NSSDC) can provide the photographs described.
A data user's note is presented which announces the availability of the complete set of Apollo 11 pictorial data and aids investigators in the selection of Apollo 11 photographs for study. In addition, this note provides guidance in the interpretation of the photographs. As background information, brief descriptions of the Apollo 11 mission objectives, photographic equipment, and photographic coverage and quality are included. The National Space Science Data Center (NSSDC) can provide all forms of photographs described in the section on format of available data.