Editing Sunset (section)

==Location on the horizon==
{{further|Solar azimuth angle}}
[[File:Sunset tokyoarea-timelapse-2019-03-17.webm|thumb|A video time lapse of a sunset in [[Tokyo]]]]

Approximate locations of sunset on the horizon ([[azimuth]]) as described above can be found in Refs.<ref>{{cite web |author=Karen Masters |date=October 2004 |title=Curious About Astronomy: How does the position of Moonrise and Moonset change? |url=https://curious.astro.cornell.edu/our-solar-system/the-moon/46-our-solar-system/the-moon/observing-the-moon/128-how-does-the-position-of-moonrise-and-moonset-change-intermediate |access-date=2016-08-11 |work=Curious About Astronomy? Ask an Astronomer |publisher=Cornell University Astronomy Department}}</ref><ref>{{cite web  |url=http://solar-center.stanford.edu/AO/sunrise.html |publisher=Stanford Solar Center |title=Where Do the Sun and Stars Rise? |access-date=2012-03-20}}</ref>
The figure on the right is calculated using the solar geometry routine as follows:<ref name="Zhangetal">Zhang, T., Stackhouse, P.W., Macpherson, B., and Mikovitz, J.C., 2021. A solar azimuth formula that renders circumstantial treatment unnecessary without compromising mathematical rigor: Mathematical setup, application and extension of a formula based on the subsolar point and atan2 function. ''Renewable Energy'', 172, 1333-1340. DOI: https://doi.org/10.1016/j.renene.2021.03.047</ref>

# For a given latitude and a given date, calculate the declination of the Sun using <math>0^{\circ}</math> longitude and [[solar noon]] time as inputs to the routine;
# Calculate the sunset hour angle using the [[sunset equation]];
# Calculate the sunset time, which is the solar noon time plus the sunset hour angle in degree divided by 15;
# Use the sunset time as input to the solar geometry routine to get the solar azimuth angle at sunset.

An interesting feature in the figure on the right is apparent hemispheric symmetry in regions where daily sunrise and sunset actually occur. This symmetry becomes clear if the hemispheric relation in [[sunrise equation]] is applied to the x- and y-components of the solar vector presented in Ref.<ref name="Zhangetal" /> Solar geometry routines that model solar azimuth angles at sunset permit the calculation using latitude, date, and time parameters to be done precisely.<ref>{{Cite web |last=Team |first=GML Web |title=Solar Calculator - NOAA Global Monitoring Laboratory |url=https://gml.noaa.gov/grad/solcalc/index.html |access-date=2024-12-10 |website=gml.noaa.gov |language=en}}</ref>