4/20/2023 0 Comments Magnitude physics calculatorThe Fe xi line is found to be the brightest, followed by Fe x and Fe xiv (in disk B ⊙ units). The morphology of the corona was typical of solar minimum, with a dipole field dominance showcased by large polar coronal holes and a broad equatorial streamer belt. We present the spatially resolved absolute brightness of the Fe x, Fe xi, and Fe xiv visible coronal emission lines from 1.08 to 3.4 R ⊙, observed during the 2019 July 2 total solar eclipse (TSE). Even with these simple conditions it is possible to come quite close to the value of the Earth’s albedo. ![]() Assuming the reflection properties of a Lambert sphere-an ideal diffuse reflecting body-for the Earth, and using measurements of the phase function-as a description for the angular distribution of the scattered light-of the Moon, the Earth’s albedo is determined from self-acquired data. In this paper, the procedure will be reproduced using simple instruments. A comparison of the intensities between the directly illuminated side of the Moon and the side illuminated by Earth’s shine provides the mean albedo for a large part of the Earth’s surface. In fact, the albedo can be determined by a basically simple procedure based on the observation of a well-known phenomenon: Earth’s shine. In tasks such as the simplified estimation of the mean temperature, it is usually given as a constant, without mentioning its determination and the associated difficulties. The Earth’s albedo, as the fraction of sunlight that is directly reflected back into space from the surface or clouds, is a key factor in modeling Earth’s climate. This paper will motivate the students and teachers of physics to look for the illuminated Moon by earthlight during the waning or waxing crescent phase of the Moon and to reproduce the expressions derived here by making use of the inverse-square law of radiation, Planck’s expression for the power in electromagnetic radiation, photopic spectral luminous efficiency function and expression for the apparent magnitude of a body in terms of luminous fluxes. The earthshine value -3.22 reported by Jackson lies within these apparent magnitudes. The corresponding values are -1.30 and -3.69, respectively. ![]() The expression for the earthshine light in terms of the apparent magnitude has been derived for the first time and evaluated for two extreme cases firstly, when the Sun’s rays are reflected by the water of the oceans and secondly when the reflector is either thick clouds or snow. The measure of the earthshine light is luminance, which is defined in photometry as the total luminous flux of light hitting or passing through a surface. ![]() As the amount of light reflected from the Earth depends on part of the Earth and the cloud cover, the strength of earthshine varies throughout the year. The Moon provides a dim light to the Earth whereas the Earth illuminates the Moon with somewhat brighter light which can be seen from the Earth and is called earthshine. The Sun illuminates Moon and the Earth both, with practically the same luminous fluxes which are in turn reflected by them.
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