Astronomical Observatory of Kharkov National University Department of Solar, Lunar and Planetary Physics
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1999-2004 Astronomical Institute of Kharkov University. Department of Solar, Lunar and Planetary Physics

Lunar Research. Publications

Velikodsky Yu.I. (2002) The Influence of Albedo and Relief on the Law of Brightness Distribution over Lunar Disk // Thesis for a degree of candidate of physical and mathematical sciences (Ph.D.). -Kharkov. In Russian.

The dissertation is devoted to the experimental study of the law of light reflection by the Moon. The empirical formula of phase dependence of the smoothness factor of lunar surface in an interval of phase angles 0-135° is obtained, that permits to perform the comparative analysis of optical properties of the all lunar disk. Using a theory describing light scattering by porous surfaces, absence of essential influence of albedo on latitude dependence of brightness of a lunar surface is proved. It is shown, that at phase angles, at least, up to 142°, the smoothness factor q is determined only by a relief practically for all surface of the Moon. On the basis of the space data it is shown, that the smoothness factor of some flat mare areas, as against the rest of lunar surface, depends on albedo. It is related to low degree of a roughness of these areas.

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Yu.I.Velikodsky, L.A.Akimov, and V.V.Korokhin (2002). The Latitude Dependance of Brightness of the Lunar Surface // Lunar and Planet. Sci. 33-rd. Abstract #1860. LPI. Houston.

It was obtained values of parameter of empirical Akimov's formula for different types of the lunar surface. Spectral dependance of this parameter was studied.

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Akimov L.A., Velikodsky Yu.I., and Korokhin V.V. (2000) Dependence of Latitude Brightness Distribution Over the Lunar Disk on Albedo and Relief "Kinematika i fisika nebesnykh tel.", in press., in Russian.

Results of brightness distribution measurements of the lunar disk and laboratory samples at different phase angles in blue and red spectral bands are presented. It is shown for the Moon that brightness falling with photometric latitude is formed mainly by micro- and mesorelief of its surface. Small decreasing of brightness falling with wavelength is due to not so much albedo changing as changing of microrelief size range which has an influence on the law of light reflection by the Moon.

Akimov L.A., Velikodsky Yu.I., Korokhin V.V. (1999) Dependence of Lunar Highlands Brightness on Photometric Latitude // Kinematika i fisika nebesnykh tel. -1999. -V.15, No 4. -P.304-309. In Russian.

Results of photometric measurements of the Moon at different phase angles are presented. Brightness distribution as the function of photometric latitude has been studied. It is shown that brightness falling to poles increases with phase angle a, and at a~120° the Moon reflects nearly by the Lambert's law. The origin of such phenomenon is discussed.


The procedure is described of Lunar surface brightness observations using the photopolarimeter with one-dimensional CCD and personal computer. The algorithms are developed for initial processing of measurements, reduction of observations to standard conditions and construction of equigonal albedo maps. The maps will be used to construct the parameters maps of phase dependence of lunar surface brightness.

V.V.Korokhin, L.A.Akimov (1997-1) MAPPING OF THE PHASE PARAMETERS OF THE LUNAR SURFACE BRIGHTNESS Astronomicheskii Vestnic, 1997, v.31, No 2, pp.143-152 [Solar System Research (Engl. transl.), 1997, v.31, No 2, pp.128-136]

A tecnique for mapping the parameters of the phase dependence of lunar-surface brightness is described. The effect of the lunar relief on the brightness phase dependence is considered and a method for eliminating such an influence is proposed. The possibility of revealing the lunar relief from photometric observations is pointed out. The dependence of the so-called effective roughness coefficient on albedo is investigated. The possibility to determine the relative age of lunar formations from the analysis of roughness is demostrated.

V.V.Korokhin (1997-2) ZONING OF THE LUNAR SURFACE BY PARAMETERS OF BRIGHTNESS-PHASE RELATION. Kinematika i Fisika Nebeshykh tel, 1997, v.31, No 6, pp.484-490 [Solar System Research (Engl. transl.), 1997, v.31, No 6, pp.430-435]

An analysis is done for distribution of parameters of brightness-phase relation over the lunar. For this purpose two-dimensional histogram (correlation diagram) diffuse albedo - effective roughness coefficient is constructed and analyzed. On the base of claster analysis of this histogram, two-parameter zoning of the Moon's visible hemisphere is carried out. Also, the regions of lunar surface with extreme values of diffuse albedo and effective roughness coefficient are visualized. A possibility to estimate the degree of lunar-soil maturity from the analysis of the parameters of the brightness-phase relation is pointed out.

Yu.G.Shkuratov, D.G.Stankevich, A.A.Ovcharenko and V.V.Korokhin (1997) A STUDY OF LIGHT BACK SCATTERING FROM PLANETARY-REGOLITH- TYPE SURFACES AT PHASE ANGLEG 0.2-3.5 DEGREES. Astronomicheskii Vestnic, 1997, v.31, No 1, pp.56-63 [Solar System Research (Engl. transl.), 1997, v.31, No 1, pp. - ]

This work is devoted to studying the photometric properties of disperse samples, which are structural analogs of the surfaces of atmosphereless celestial bodies at extremely small phase angles. The phase dependences of brightness were measured with a laboratory small-phase-angle photometer designed and built at the Astronomical Observatory of Kharkov State University. The majority of dielectric materials exhibited the opposition spike with an amplitude of about 20% at phase angles ranging from 0.2 to 3.5 degrees. Palagonite, which is a spectral analog of the Martian soil, showed the so-called anomalous opposition color revealed earlier measurements of the lunar soil. It is shown that the opposition brightness spike of the Moon discovered by spacecraft Clementine is likely a consequence of incorrect data analysis, since the width of this spike is less then the angular size of the light source (the Sun). The phase dependence of brightness for an ash sample is presented and considered to be a model for the lunar phase curve in the phase-angle range 0.2-30 degrees. The amplitude of the opposition spike of this "moon" is 1.35 in the phase-angle interval 0.2-5.0 degrees.

Yu.I.Velikodsky, L.A.Akimov, and V.V.Korokhin. (2000) Two-parameter Empirical Photometric Function in Analysis of Earth-based Observations of the Moon // Lunar and Planet. Sci. 30-th. Abstract #1391. 2000. LPI. Houston.

Improved empirical Akimov's formula is presented. This photometric function gives a good fit to Earth-based and Clementine observational data. An influence of albedo and relief on the disk brightness distribution is discussed.

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