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azimuth and altitude.
The method is taken from equations 8.5 and 8.6 of reference 1, or, equivalently,
from equations 12.5 and 12.6 of reference 2."><meta property="og:description" content="Convert from equatorial coordinates to local horizontal coordinates, i.e.
azimuth and altitude.
The method is taken from equations 8.5 and 8.6 of reference 1, or, equivalently,
from equations 12.5 and 12.6 of reference 2."></head><body>
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      <h1>Convert Equatorial Coordinate to Local Horizontal Coordinate</h1>
      <small class="dont-index">Source: <a href="https://github.com/dankelley/oce/blob/HEAD/R/astronomy.R" class="external-link"><code>R/astronomy.R</code></a></small>
      <div class="d-none name"><code>equatorialToLocalHorizontal.Rd</code></div>
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    <div class="ref-description section level2">
    <p>Convert from equatorial coordinates to local horizontal coordinates, i.e.
azimuth and altitude.
The method is taken from equations 8.5 and 8.6 of reference 1, or, equivalently,
from equations 12.5 and 12.6 of reference 2.</p>
    </div>

    <div class="section level2">
    <h2 id="ref-usage">Usage<a class="anchor" aria-label="anchor" href="#ref-usage"></a></h2>
    <div class="sourceCode"><pre class="sourceCode r"><code><span><span class="fu">equatorialToLocalHorizontal</span><span class="op">(</span></span>
<span>  <span class="va">rightAscension</span>,</span>
<span>  <span class="va">declination</span>,</span>
<span>  <span class="va">t</span>,</span>
<span>  <span class="va">longitude</span>,</span>
<span>  <span class="va">latitude</span></span>
<span><span class="op">)</span></span></code></pre></div>
    </div>

    <div class="section level2">
    <h2 id="arguments">Arguments<a class="anchor" aria-label="anchor" href="#arguments"></a></h2>


<dl><dt id="arg-rightascension">rightAscension<a class="anchor" aria-label="anchor" href="#arg-rightascension"></a></dt>
<dd><p>right ascension, e.g. calculated with
<code><a href="eclipticalToEquatorial.html">eclipticalToEquatorial()</a></code>.</p></dd>


<dt id="arg-declination">declination<a class="anchor" aria-label="anchor" href="#arg-declination"></a></dt>
<dd><p>declination, e.g. calculated with
<code><a href="eclipticalToEquatorial.html">eclipticalToEquatorial()</a></code>.</p></dd>


<dt id="arg-t">t<a class="anchor" aria-label="anchor" href="#arg-t"></a></dt>
<dd><p>time of observation.</p></dd>


<dt id="arg-longitude">longitude<a class="anchor" aria-label="anchor" href="#arg-longitude"></a></dt>
<dd><p>longitude of observation, positive in eastern hemisphere.</p></dd>


<dt id="arg-latitude">latitude<a class="anchor" aria-label="anchor" href="#arg-latitude"></a></dt>
<dd><p>latitude of observation, positive in northern hemisphere.</p></dd>

</dl></div>
    <div class="section level2">
    <h2 id="value">Value<a class="anchor" aria-label="anchor" href="#value"></a></h2>
    <p>A data frame containing columns <code>altitude</code> (angle above
horizon, in degrees) and <code>azimuth</code> (angle anticlockwise from south, in
degrees).</p>
    </div>
    <div class="section level2">
    <h2 id="references">References<a class="anchor" aria-label="anchor" href="#references"></a></h2>

<ul><li><p>Meeus, Jean. Astronomical Formulas for Calculators. Second Edition.
Richmond, Virginia, USA: Willmann-Bell, 1982.</p></li>
<li><p>Meeus, Jean. Astronomical Algorithms. Second Edition.
Richmond, Virginia, USA: Willmann-Bell, 1991.</p></li>
</ul></div>
    <div class="section level2">
    <h2 id="see-also">See also<a class="anchor" aria-label="anchor" href="#see-also"></a></h2>
    <div class="dont-index"><p>Other things related to astronomy:
<code><a href="angle2hms.html">angle2hms</a>()</code>,
<code><a href="eclipticalToEquatorial.html">eclipticalToEquatorial</a>()</code>,
<code><a href="julianCenturyAnomaly.html">julianCenturyAnomaly</a>()</code>,
<code><a href="julianDay.html">julianDay</a>()</code>,
<code><a href="moonAngle.html">moonAngle</a>()</code>,
<code><a href="siderealTime.html">siderealTime</a>()</code>,
<code><a href="sunAngle.html">sunAngle</a>()</code>,
<code><a href="sunDeclinationRightAscension.html">sunDeclinationRightAscension</a>()</code></p></div>
    </div>
    <div class="section level2">
    <h2 id="author">Author<a class="anchor" aria-label="anchor" href="#author"></a></h2>
    <p>Dan Kelley, based on formulae in references 1 and 2.</p>
    </div>

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