Air mass: Difference between revisions
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In astronomy '''air mass''' is a measure of the amount of atmosphere between the observer and the object being observed. It is a function of the ''zenith angle'' (the angle between the line of sight an vertical) and the altitude of the observer. It is defined as the integral of the atmospheric density along the line of sight and is usually expressed relative to the air mass at zenith. Thus, looking straight up gives an air mass of one (regardless of observer's altitude) and viewing at any zenith angle greater than zero gives higher values.
You will need to integrate <math>\rho</math>(h(a,z,x)) where <math>\rho</math>(h) is the atmospheric density for a given height above sea level, and h(a,z,x) is the height above sea level for a point at distance x along the line of sight. Determining this last function requires some trigonometry.
For this task you can assume:
* The density of Earth's atmosphere is proportional to exp(-a/8500 metres)
* The Earth is a perfect sphere of radius 6731 km.
;Task:
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