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73 lines
3.1 KiB
Markdown
73 lines
3.1 KiB
Markdown
# Astronomy Engine examples in C
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### [Camera](camera.c)
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Suppose you want to photograph the Moon, and you want to know what it will look like in the photo.
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Given a location on the Earth, and a date/time, this program calculates the orientation of the sunlit
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side of the Moon with respect to the top of your photo image. It assumes the camera faces directly
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toward the Moon's azimuth and tilts upward to its altitude angle above the horizon.
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The angles are defined counterclockwise from the zenith, as shown here:
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### [Culmination](culminate.c)
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Finds when the Sun, Moon, and planets reach their highest position in the sky on a given date,
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as seen by an observer at a specified location on the Earth.
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Culmination is also the moment a body crosses the *meridian*, the imaginary semicircle
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in the sky that passes from due north on the horizon, through the zenith (straight up),
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and then toward due south on the horizon.
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### [Galactic to Horizontal Converter](galactic.c)
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A demonstration of how to convert galactic coordinates to horizontal coordinates.
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This could be useful for backyard radio astronomers who know the galactic
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coordinates of a distant radio source and want to aim a radio dish at it.
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Given the galactic coordinates, the geographic coordinates of the observer,
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and the date and time of the observation, this program shows how to
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obtain the altitude and azimuth to aim the dish at the radio source.
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### [Horizon Intersection](horizon.c)
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This is a more advanced example. It shows how to use coordinate
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transforms to find where the ecliptic intersects with an observer's
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horizon at a given date and time.
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### [Lunar Eclipse](lunar_eclipse.c)
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Calculates details about the first 10 partial/total lunar eclipses
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after the given date and time.
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### [Moon Phase Calculator](moonphase.c)
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This example shows how to determine the Moon's current phase,
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and how to predict when the next few quarter phases will occur.
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### [Positions](positions.c)
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Calculates equatorial and horizontal coordinates of the Sun, Moon, and planets.
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### [Rise/Set](riseset.c)
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Shows how to calculate sunrise, sunset, moonrise, and moonset times.
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### [Seasons](seasons.c)
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Calculates the equinoxes and solstices for a given calendar year.
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### [Solar Time](solar_time.c)
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An example of how to use the Sun's hour angle to calculate true solar time.
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### [Triangulate](triangulate.c)
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Given the geographic coordinates of two observers, and angular
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directions they are looking in, determines geographic coordinates
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of the point they are both looking at. This example demonstrates
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use of the geoid functions `VectorObserver` and `ObserverVector`
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that convert between geographic coordinates and vectors.
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### [World Map](worldmap.cpp)
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This C++ program generates a PNG image showing intensity of
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sunlight and moonlight on a Mercator projection of the Earth.
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This example is helpful for showing how to minimize per-pixel
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calculations across the globe for a given time of observation.
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---
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# [API Reference](../../source/c/)
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Complete documentation for all the functions and types available
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in the C version of Astronomy Engine.
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