Calculating the suns path in sky

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SUMMARY

This discussion focuses on calculating the Sun's path in the sky using specific equations and their implementation in a Java program. The user seeks clarity on the relationship between degrees and time constants in the equations, particularly regarding the Equation of Time (EoT), which provides results in minutes. The conversation highlights the importance of understanding unit conversions, specifically distinguishing between angular measurements in degrees and time measurements in minutes. The referenced resource, PV Education, offers valuable insights into these equations and their respective units.

PREREQUISITES
  • Basic understanding of solar path calculations
  • Familiarity with Java programming
  • Knowledge of trigonometric functions
  • Understanding of units of measurement (degrees and minutes)
NEXT STEPS
  • Research the Equation of Time (EoT) and its applications in solar calculations
  • Explore Java libraries for astronomical calculations, such as JAstro
  • Study spherical-polar coordinates and their relevance to solar path tracking
  • Examine the PV Education resource for detailed explanations of solar time and angles
USEFUL FOR

Anyone interested in solar energy applications, Java developers working on astronomical software, and researchers focusing on solar path calculations will benefit from this discussion.

dwn
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I've searched the internet and found a few sites, of varying depth, that contain some of the equations to calculating the solar path. At the moment, I'm not particularly concerned with precision. I am trying to discern the equations in order to implement them into a java program I am writing.

Some of the equations use degrees multiplied by time constants and so I'm trying to decide if I need to change the degree value to time values? The reason I ask is that my result is not a value I expected. The link provided has the series of equations I would like to use.

The equation of time uses trig functions, but says the result represents minutes. Does that mean I need to convert the degree value to minutes, or the result is already in minutes? No units are used in this case and so its a little confusing to discern.

http://www.pveducation.org/pvcdrom/properties-of-sunlight/solar-time
 
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You should start by saying what you mean by "the Sun's path in the sky".
Usually I would think of you tracking right-ascention and declination from a particular lat/long position on the Earth... but you may just be interested in tracking the spherical-polar coordinates from the center of the earth.

The web page you cite uses "minutes" for time but not for angles - it's pretty good at explaining which bit has what units.
The EoT formual gives the EoT in minutes ... but the angle B, as the following text explains, is in degrees.

In general a description "the equation gives X (in y)" tells you that the equation for X is formulated so that it comes out in units of y.
You can usually tell from the units in the body of the equation.
 

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