![]() ![]() Supposed to be picked up by the other one. To which each receptor is sensitive to the radiation that is Position-independent receptor cross-leakage (ĭescribe `leakage' between receptors, i.e. formalism offers a frameworkįor the ful description of the primary beam of any radio telescope that can be conceived. In some exotic cases, it may not be very useful toĪlways allowed. Will be more complicated for antennas with , they must be modelled as off-diagonal elements of The frontend box, or scattering off support legs, may cause For instance, standing waves between the primary mirror and In reality, things will be more complicated, especially for off-axis The resulting position-dependent difference is one cause of off-axis Of a feed will not coincide, because they are oriented differently. Obviously, the two asymmetric voltage beams Rotation of the voltage beam on the sky!.Įquation 37 illustrates that the voltage beam of aĭipole receptor will be slightly elongated in the direction of theĬircular and symmetrical. Only takes care of electrical rotation, but not of the Note that the two receptor beams are each described in their own Of the polarisation coordinate frames, there will be two different Since the orientations are defined in one Seen from the direction of the source (see also sectionĥ.6 below). ![]() The `Projection matrix' models the projected orientation of the Obvious why one would want to do such a thing, but it is good to know The receptors of a feed are practically always co-located, Kernel or `phase weight' for the baseline Multiplicative factor of the familiar form the fringe tracking centreĭiagonal matrix with equal elements. , which depends on the projected feed position Polarisation coordinate frames, there will be two different forms for Represents (ionospheric) Faraday rotation of Where possible, the expressions haveīeen reduced to matrices like the diagonal matrix ( `coupling factor' for the signal going from receptor to IF-channel. Less complete, these `standard' matrix elements could be referred toĮxplicitly by their official names in other AIPS++ documents (andĬode), for instance to replace them with specific expressions for Is that, if the structure of the Measurement Equation is more or It will be noted that for each matrix, the 4 elements have been given In this section, the `generic' form of various 2 x 2įeed-based instrumental Jones matrices (operators) will be treated Position-independent receptor cross-leakage (.Next: THE ORDER OF JONES MATRICES Up: The MEASUREMENT EQUATION of a generic radio telescope Previous: POLARISATION COORDINATES GENERIC FORM OF JONES MATRICES Getting Started ![]()
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