<p>I started using the software that comes with Jean Meeus book Astronomical Algorithms. I am now using the updated code from naughter(dot)com/aa.html. </p>

<p>I am able to calculate the heliocentric longitude and latitude for an asteroid using the orbital elements. Below is for the asteroid Juno. I can't find any source code or instructions for converting the asteroid coordinates I calculated below to geocentric longitude and latitude. Can anyone recommend a method to find asteroid geocentric longitude and latitude? Thanks. </p>

<pre><code>double Longitude = 0.0; //West Greenwich  
double Latitude  = 51.4826; //North Greenwich  
double TZOffSet = 0.0;


//Asteroid Juno Elements;   Using epoch J2000
CAAEllipticalObjectElements elements;  

//Calculation Julian Date  2017, 9, 25 
elements.JDEquinox = JD;   

elements.T = (JD - 2451545.0) / 36525.0;

//semi-major axis of the orbit
elements.a = 2.6700912;

//eccentricity of the orbit
elements.e = 0.25498122;

//inclination of the plane of the ecliptic
elements.i = 12.98211;

//Longitude of ascending node
elements.omega = 169.91138;

//longitude of perihelion
elements.w = 248.10807; 

//-------------------------------------------------------------------------
CAAEllipticalObjectDetails details = CAAElliptical::Calculate(JD, elements, true);

1) Heliocentric Ecliptic Longitude  = 215.6670202
2) Heliocentric Ecliptic Latitude = 9.377841131
3) True Geocentric RA = 13.90415220
4) True Geocentric Declination = -3.802673727
5) True Geocentric Distance = 4.136531368
6) True Geocentric Light Time = 0.0238906126
7) Astrometric Geocentric RA = 13.90397025
8) Astrometric Geocentric Declination = -3.80217202
9) Astrometric Geocentric Distance = 4.13653445
10) Astrometric Geocentric Light Time = 0.023890630
11) Elongation = 26.74464206
12) Phase Angle  = 7.928218201
//-------------------------------------------------------------------------
</code></pre>

<asteroids><coordinate><ephemeris><algorithm>
Finding Asteroid Geocentric Longitude and Latitude
homebase
# Finding Asteroid Geocentric Longitude and Latitude

(Asked by: username_0 on 2017-09-27)

I started using the software that comes with Jean Meeus book Astronomical Algorithms. I am now using the updated code from naughter(dot)com/aa.html. 
I am able to calculate the heliocentric longitude and latitude for an asteroid using the orbital elements. Below is for the asteroid Juno. I can't find any source code or instructions for converting the asteroid coordinates I calculated below to geocentric longitude and latitude. Can anyone recommend a method to find asteroid geocentric longitude and latitude? Thanks. 
double Longitude = 0.0; //West Greenwich  
double Latitude  = 51.4826; //North Greenwich  
double TZOffSet = 0.0;


//Asteroid Juno Elements;   Using epoch J2000
CAAEllipticalObjectElements elements;  

//Calculation Julian Date  2017, 9, 25 
elements.JDEquinox = JD;   

elements.T = (JD - 2451545.0) / 36525.0;

//semi-major axis of the orbit
elements.a = 2.6700912;

//eccentricity of the orbit
elements.e = 0.25498122;

//inclination of the plane of the ecliptic
elements.i = 12.98211;

//Longitude of ascending node
elements.omega = 169.91138;

//longitude of perihelion
elements.w = 248.10807; 

//-------------------------------------------------------------------------
CAAEllipticalObjectDetails details = CAAElliptical::Calculate(JD, elements, true);

1) Heliocentric Ecliptic Longitude  = 215.6670202
2) Heliocentric Ecliptic Latitude = 9.377841131
3) True Geocentric RA = 13.90415220
4) True Geocentric Declination = -3.802673727
5) True Geocentric Distance = 4.136531368
6) True Geocentric Light Time = 0.0238906126
7) Astrometric Geocentric RA = 13.90397025
8) Astrometric Geocentric Declination = -3.80217202
9) Astrometric Geocentric Distance = 4.13653445
10) Astrometric Geocentric Light Time = 0.023890630
11) Elongation = 26.74464206
12) Phase Angle  = 7.928218201
//-------------------------------------------------------------------------

**Tags:** asteroids, coordinate, ephemeris, algorithm

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## 0 answers

