Editing Circular polarization (section)

=== Uses of the two conventions ===

As stated earlier, there is significant confusion with regards to these two conventions. As a general rule, the engineering, quantum physics, and radio astronomy communities use the first convention, in which the wave is observed from the point of view of the source.<ref name=Orfanidis /><ref name="Lectures_on_Physics(Vol_1_ch_33-1)" /><ref name=IAU /> In many physics textbooks dealing with optics, the second convention is used, in which the light is observed from the point of view of the receiver.<ref name="Lectures_on_Physics(Vol_1_ch_33-1)" /><ref name="Polarization_in_Spectral_Lines_Section_1.2" />

To avoid confusion, it is good practice to specify "as defined from the point of view of the source" or "as defined from the point of view of the receiver" when discussing polarization matters.

The archive of the [https://web.archive.org/web/20090822015912/http://www.its.bldrdoc.gov/fs-1037/ US Federal Standard 1037C] proposes two contradictory conventions of handedness.<ref>In one location it is stated..."Note 1. ... In general, the figure, i.e., polarization, is elliptical and is traced in a clockwise or anti-clockwise sense, as viewed in the direction of propagation. ... Rotation of the electric vector in a clockwise sense is designated right-hand polarization, and rotation in an anti-clockwise sense is designated left-hand polarization. "[http://www.its.bldrdoc.gov/fs-1037//dir-028/_4059.htm] {{Webarchive|url=https://web.archive.org/web/20110514080812/http://www.its.bldrdoc.gov/fs-1037/dir-028/_4059.htm|date=2011-05-14}} In another location it is stated... "Note 4: Circular polarization may be referred to as "right-hand" or "left-hand", depending on whether the helix describes the thread of a right-hand or left-hand screw, respectively". [http://www.its.bldrdoc.gov/fs-1037/dir-007/_0972.htm] {{Webarchive|url=https://web.archive.org/web/20110606113103/http://www.its.bldrdoc.gov/fs-1037/dir-007/_0972.htm|date=2011-06-06}}</ref>

Note that the IEEE defines RHCP and LHCP the opposite as those used by physicists.  The IEEE 1979 Antenna Standard will show RHCP on the South Pole of the Poincare Sphere. The IEEE defines RHCP using the right hand with thumb pointing in the direction of transmit, and the fingers showing the direction of rotation of the E field with time.  The rationale for the opposite conventions used by Physicists and Engineers is that Astronomical Observations are always done with the incoming wave traveling toward the observer, where as for most engineers, they are assumed to be standing behind the transmitter watching the wave traveling away from them.  This article is not using the IEEE 1979 Antenna Standard and is not using the +t convention typically used in IEEE work.