Changes

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[[Image:lighterstill.jpg]][[Image:Focalpointflame180.jpg|right|frame]]

In geometrical [[optics]], a '''focus''', also called an '''image point''', is the point where [[light]] rays originating from a point on the object converge [http://www.charfac.umn.edu/glossary/f.html]. Although the focus is conceptually a point, physically the focus has a spatial extent, called the ''blur circle''. This non-[[ideal]] focusing may be caused by aberrations of the imaging optics. In the absence of significant aberrations, the smallest possible blur circle is the Airy disc, which is caused by diffraction from the optical system's apertur]. Aberrations tend to get worse as the aperture diameter increases, while the Airy circle is smallest for large apertures.

In geometrical [[optics]], a '''focus''', also called an '''image point''', is the point where [[light]] rays originating from a point on the object converge [https://www.charfac.umn.edu/glossary/f.html]. Although the focus is conceptually a point, physically the focus has a spatial extent, called the ''blur circle''. This non-[[ideal]] focusing may be caused by aberrations of the imaging optics. In the absence of significant aberrations, the smallest possible blur circle is the Airy disc, which is caused by diffraction from the optical system's apertur]. Aberrations tend to get worse as the aperture diameter increases, while the Airy circle is smallest for large apertures.

An image, or image point or region, is '''''in focus''''' if light from object points is converged almost as much as possible in the image, and '''''out of focus''''' if light is not well converged.  The border between these is sometimes defined using a circle of confusion criterion.

An image, or image point or region, is '''''in focus''''' if light from object points is converged almost as much as possible in the image, and '''''out of focus''''' if light is not well converged.  The border between these is sometimes defined using a circle of confusion criterion.

In the [[gravity|gravitation]]al two-body problem, the orbits of the two bodies are described by two overlapping conic sections each with one of their foci being coincident at the center of mass (barycenter).

In the [[gravity|gravitation]]al two-body problem, the orbits of the two bodies are described by two overlapping conic sections each with one of their foci being coincident at the center of mass (barycenter).

==Quote==

==Quote==

"You cannot truly [[love]] your fellows by a mere act of the [[volition|will]]. Love is only born of thoroughgoing understanding of your neighbor's motives and sentiments. It is not so important to love all men today as it is that each day you learn to love one more [[human being]]. If each day or each week you achieve an understanding of one more of your fellows, and if this is the limit of your ability, then you are certainly socializing and truly [[Spirituality|spiritualizing]] your [[personality]]. Love is infectious, and when human devotion is [[intelligence|intelligent]] and [[wisdom|wise]], love is more catching than hate. But only genuine and unselfish [[love]] is truly contagious. If each mortal could only become a <u>'''''focus'''''</u> of dynamic [[affection]], this benign virus of love would soon pervade the sentimental [[emotion]]-stream of [[humanity]] to such an extent that all [[civilization]] would be encompassed by love, and that would be the [[Reality|realization]] of the brotherhood of man."[http://urantia.org/cgi-bin/webglimpse/mfs/usr/local/www/data/papers?link=http://mercy.urantia.org/papers/paper100.html&file=/usr/local/www/data/papers/paper100.html&line=86#mfs]

"You cannot truly [[love]] your fellows by a mere act of the [[volition|will]]. Love is only born of thoroughgoing understanding of your neighbor's motives and sentiments. It is not so important to love all men today as it is that each day you learn to love one more [[human being]]. If each day or each week you achieve an understanding of one more of your fellows, and if this is the limit of your ability, then you are certainly socializing and truly [[Spirituality|spiritualizing]] your [[personality]]. Love is infectious, and when human devotion is [[intelligence|intelligent]] and [[wisdom|wise]], love is more catching than hate. But only genuine and unselfish [[love]] is truly contagious. If each mortal could only become a <u>'''''focus'''''</u> of dynamic [[affection]], this benign virus of love would soon pervade the sentimental [[emotion]]-stream of [[humanity]] to such an extent that all [[civilization]] would be encompassed by love, and that would be the [[Reality|realization]] of the brotherhood of man."[https://urantia.org/cgi-bin/webglimpse/mfs/usr/local/www/data/papers?link=https://mercy.urantia.org/papers/paper100.html&file=/usr/local/www/data/papers/paper100.html&line=86#mfs]

== References ==

== References ==