|The Conventions for the Polarization Angle
|526, Solar Polarization Workshop 8
|di Serego Alighieri, S.
|Since more than a century astronomers measure the position angle of the major axis of the polarization ellipse starting from the North direction and increasing counter-clockwise, when looking at the source. This convention has been enforced by the IAU with a Resolution in 1973. Much later the WMAP satellite, which has observed the polarization of the cosmic microwave background, has unfortunately adopted the opposite convention: the polarization position angle is measured starting from the South and increasing clockwise, when looking at the source. This opposite convention has been followed by most cosmic microwave background polarization experiments and is causing obvious problems and misunderstandings. The attempts and prospects to enforce the official IAU convention are described.
This article, presented in a poster at this Workshop,
has been published on
Experimental Astronomy (di Serego Alighieri 2017),
and is not reproduced here to avoid duplications.