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Lloyd, D. D.

Publications and source records attributed to Lloyd, D. D..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Near-terminator photography, part R

The advantages resulting from the use of near-terminator photography in lunar surface investigations are discussed. It is pointed out that, under near-terminator conditions, small changes in slope produce greater contrast changes than at high sun elevation angles. This desirable phenomenon is confirmed by an examination of the near-terminator photography taken during the Apollo 15 mission. Many of the photographs obtained show lunar surface areas within a few degrees of the terminator and are therefore of significant geologic interest. In addition, many geologic features stand out in a distinct manner not normal in conventional lunar photography, thus providing additional data on the surface morphology and the configuration of a large number of lunar surface structures.

Head, J. W.↗
NASA NTRS1972

First earthshine photography from lunar orbit, part S

The first photographs of the moon taken with earthshine illumination by the Apollo 15 crew were examined. Emphasis in the analysis was placed on a comparison of predicted exposures and obtained exposures. The results of the investigation indicate the following: (1) The predicted exposure of the maria areas and the obtained exposures were in reasonably close agreement. (2) The apparent-albedo values obtained for the floor of Aristarchus Crater are seven times greater than those for the maria.

Lloyd, D. D.↗
NASA NTRS1972

Orientale Basin deposits (Riccioli area) in Apollo 16 earthshine photography, part E

Interpretations of photography of Orientale Basin deposits obtained under earthshine illumination conditions during the Apollo 16 mission are presented. Although the quality of these photographs is less than that obtainable in sunshine, these regions are in the dark during Apollo missions because of the locations of the Apollo landing sites. Photography of these regions under different lighting geometry and from different viewpoints is therefore a useful addition to previous photographic data. Oblique photography was obtained of Riccioli Crater and adjacent areas, which lie northeast of the Orientale Basin.

Lloyd, D. D.↗
NASA NTRS1972

Low relief features in terrain of the Decartes region and other areas: Near terminator photography, part U

Primary efforts were made to outline areas where low-relief features in the Apollo 16 landing site and associated plains and mare units were intensified in near-terminator photography. A description and, in some cases, a preliminary interpretation of several of these areas is included in an attempt to provide additional data relevant to the interpretation of the hills, plains, and associated units investigated on the Apollo 16 mission. Near-terminator photography for areas discussed is listed in a table.

Head, J. W.↗
NASA NTRS1971

First Earthshine photography from lunar orbit

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.

Lloyd, D. D.↗