<?xml version="1.0" encoding="ISO-8859-1"?><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
<front>
<journal-meta>
<journal-id>0185-1101</journal-id>
<journal-title><![CDATA[Revista mexicana de astronomía y astrofísica]]></journal-title>
<abbrev-journal-title><![CDATA[Rev. mex. astron. astrofis]]></abbrev-journal-title>
<issn>0185-1101</issn>
<publisher>
<publisher-name><![CDATA[Universidad Nacional Autónoma de México, Instituto de Astronomía]]></publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id>S0185-11012022000100037</article-id>
<article-id pub-id-type="doi">10.22201/ia.01851101p.2022.58.01.03</article-id>
<title-group>
<article-title xml:lang="en"><![CDATA[Off-Axis Exact Ray Tracing Algorithm for Zero Coma Point Determination in Classical and Non-Classical Reflective Telescopes]]></article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Herrera]]></surname>
<given-names><![CDATA[J.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Najera]]></surname>
<given-names><![CDATA[M. R.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
<contrib contrib-type="author">
<name>
<surname><![CDATA[Guerrero]]></surname>
<given-names><![CDATA[C. A.]]></given-names>
</name>
<xref ref-type="aff" rid="Aff"/>
</contrib>
</contrib-group>
<aff id="Af1">
<institution><![CDATA[,Universidad Nacional Autónoma de México Instituto de Astronomía ]]></institution>
<addr-line><![CDATA[Ensenada B. C.]]></addr-line>
<country>Mexico</country>
</aff>
<pub-date pub-type="pub">
<day>00</day>
<month>00</month>
<year>2022</year>
</pub-date>
<pub-date pub-type="epub">
<day>00</day>
<month>00</month>
<year>2022</year>
</pub-date>
<volume>58</volume>
<numero>1</numero>
<fpage>37</fpage>
<lpage>45</lpage>
<copyright-statement/>
<copyright-year/>
<self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_arttext&amp;pid=S0185-11012022000100037&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_abstract&amp;pid=S0185-11012022000100037&amp;lng=en&amp;nrm=iso"></self-uri><self-uri xlink:href="http://www.scielo.org.mx/scielo.php?script=sci_pdf&amp;pid=S0185-11012022000100037&amp;lng=en&amp;nrm=iso"></self-uri><abstract abstract-type="short" xml:lang="en"><p><![CDATA[ABSTRACT In this work we present a general algorithm to calculate the zero coma point for classical and non-classical reflecting telescopes with aspherical surfaces. We programmed a general ray tracing function applicable to conical surfaces with asphericity, displacements, and inclinations that can be modified by the users, according to their specifications. This function is used to evaluate the transverse coma and determine the optimal conjunction of shift and tilt of the secondary mirror that prevents the introduction of axial coma during the collimation process. We present the calculation of the zero coma point for the classical telescopes of the National Astronomical Observatory, San Pedro Mártir, Mexico. Furthermore, we show an example of a wide-field telescope with aspherical surfaces, as will be the case of the TAOS-II telescopes, for which the classical analytical expression cannot be used.]]></p></abstract>
<abstract abstract-type="short" xml:lang="es"><p><![CDATA[RESUMEN En este trabajo presentamos un algoritmo general para calcular el punto de coma cero para telescopios reflectores clásicos y no clásicos con superficies asféricas. Programamos una función de trazado de rayos general aplicable a superficies cónicas con asfericidad, desplazamientos e inclinaciones, que puede ser modificada por los usuarios, según sus especificaciones. Esta función se utiliza para evaluar la coma transversal y determinar la conjunción óptima de desplazamiento e inclinación del espejo secundario que evita la introducción de coma axial durante el proceso de colimación. Presentamos el cálculo del punto de coma cero para los telescopios clásicos del Observatorio Astronómico Nacional, San Pedro Mártir, México. Además, mostramos el ejemplo de un telescopio de campo amplio con superficies asféricas, como será el caso de los telescopios TAOS-II, para los que no se puede utilizar la expresión analítica clásica.]]></p></abstract>
<kwd-group>
<kwd lng="en"><![CDATA[telescopes]]></kwd>
</kwd-group>
</article-meta>
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