Solar declination

The local zenith angle / varies with time of day, season, geographic location. For example, at latitude 0 and a solar declination S, x varies with local hour angle, fh> according to (fh = 0 at local noon). 

The second parameter that is needed for the calculation of the solar zenith angle at a particular time and place is the solar declination, S, defined as the angle between the direction of the sun and the equatorial plain of the earth. The value of S (in radian) can be calculated as follows ... 

Solar Declination - The apparent angle of the sun north or south of the eath s equatorial plane. The earth s rotation on its axis causes a daily change in the declination. 

Here is a declination, which adds the angle between the earth axis and direction to the sun disk center to 7t/2. Solar declination sine J as a function of n daytime from the beginning of the year is expressed by the following formula ... 

The solar zenith angle 6 necessary to calculate air mass in Eq. (3.4) can be obtained from the latitude q> (degree), solar declination 5 (radian), and hour angle h (radian). 

Solar water heating declined in Southern California in the 1920s due to the development of natural gas, but it continued in Florida where natural gas was very expensive. In 1941 more than half Miami s population had solar water heaters, and more than 80 percent of new homes built then were equipped with solar water heaters. By the end of the 1950s in Florida, solar water heating was displaced by electricity as the price dropped and the storage tanks of solar water heaters failed because of galvanic corrosion from connecting steel tanks to copper collectors. 

Tax credits were provided for solar water heating systems in response to the energy crisis. After tax credits expired, the solar water heater business declined drastically. The only segment of solar water heater market that has continued to have growth is the pool heater. 

Abstract. We present the results of an observational campaign undertaken to assess the influence of the iron content on the Cepheid Period-Luminosity relation. Our data indicate that this dependence is not well represented by a simple linear relation. Rather, the behaviour is markedly non monotonic, with the correction peaking at about solar metallicity and declining for higher and lower values of [Fe/H]. 

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