# Position and angle of Earth/Moon/Sun and timing

• TouTorp
In summary, the speaker is looking for help in building a program to calculate the angles of the Earth, moon, and sun relative to each other. They are limited to starting from scratch and are unsure of how to find the relative angles of these frames at different times. They have been searching for resources but have not found a solution yet. The suggested starting point is the Heliocentric frame and using NASA JPL's ephemeris.
TouTorp
Hello all, I made an account here some time ago but hadn't got around to using it.

I'd quite like to build a program for getting the angle of the Earth compared to vernal equniox (so I can convert from ECI to ECEF co-ordinates), angle of the moon relative to the earth, and angle of the sun relative to the earth.

There may be existing programs capable of doing so, but I'm intending to put this on a microcontroller, so are really going to be limited to doing this from scratch.

I think I'm going to be fine with the angle conversions and getting into different frames, but the issue is I don't know how to find out what the relative angles of these frames will be at different times. Say I want to know on September 18th 2013 at 20:00 GMT what the RA and DEC of the sun and moon will be, and I want to know what the angle of the Earth will be compared to the celestial sphere, so I can get to what position they will be in the local sky at a given longitude and latitude.

Problem is, there are so many resources out there I really don't know where to start, been searching the past few days and still drawing a blank with what I need to be doing.

Any help would be much appreciated. Thanks!

Torpedo

It is easiest to start in the Heliocentric frame then convert to the Geocentric Equatorial.

Nasa JPL has an Ephemeris that is helpful.

http://ssd.jpl.nasa.gov/?planet_pos

## 1. How does the position of the Earth affect the seasons?

The Earth's position in relation to the Sun determines the amount of sunlight that reaches different parts of the Earth, which in turn affects the seasons. When the Earth is tilted towards the Sun, the Northern Hemisphere experiences summer while the Southern Hemisphere experiences winter. When the Earth is tilted away from the Sun, the opposite occurs.

## 2. What causes lunar and solar eclipses?

Lunar eclipses occur when the Earth passes between the Sun and the Moon, casting a shadow on the Moon. Solar eclipses occur when the Moon passes between the Sun and the Earth, blocking the Sun's light from reaching certain parts of the Earth.

## 3. How do scientists determine the position and angle of the Earth, Moon, and Sun?

Scientists use various tools and methods such as telescopes, satellites, and mathematical calculations to observe and track the positions and angles of the Earth, Moon, and Sun. They also take into account the Earth's orbit around the Sun and the Moon's orbit around the Earth.

## 4. Why does the Moon appear to change shape throughout the month?

The Moon's shape changes throughout the month due to its orbit around the Earth. As the Moon moves around the Earth, different amounts of sunlight are reflected off its surface, causing it to appear to change shape from our perspective on Earth.

## 5. How does the timing of the Earth's rotation and revolution affect our daily lives?

The Earth's rotation on its axis and its revolution around the Sun determine the length of our days and years. Our daily lives are affected by the amount of sunlight we receive, which impacts our sleep patterns, agriculture, and overall daily routines.

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