The Ohio Sky Survey and other radio surveys

Systematic effects in the measurement of polarization by the PLANCK telescope

“…Following standard conventions (Kraus 1982), PLANCK will measure Stokes parameters I, Q and U by combining the output of four linearly polarized detectors; a first pair having principal planes of polarization at right angles to each other and a second pair with principal planes of polarization at right angles as well, but rotated by 45…”

“…In this way, by combining samples from several linearly polarized detectors, it is possible to extract all the polarization information in terms of the Stokes parameters (see e.g., Kraus 1982;Couchot et al 1999). However, an optimal measurement relies critically on the similarity of the polarized angular responses, also called beam or radiation patterns, of the differently oriented polarized horns.…”

Calibration of planetary brightness temperature spectra at near-millimeter and submillimeter wavelengths with a Fourier-transform spectrometer

“…The value of this integral is of course determined entirely by the properties of the telescope beam, which in general consist of three components: a narrow main beam, which results from diffraction by the full aperture, a broader and much weaker error pattern, which is caused by panel misalignment and surface imperfections, and a wide-angle component, which is due primarily to beam spillover past the secondary [20][21][22][23][24][25] 1note that atmospheric seeing fluctuations are unimportant at these long wavelengths2. Conversion from T* A 1n2 to T p 1n2 is thus in general nontrivial, even for simple disklike sources.…”

“…The equations of radiative transfer and antenna theory, together with the inclusion of port 2 emission, then lead to the following equation for the blank sky 1off 2 voltage spectrum 18,[20][21][22][23][24][25] :…”

“…Note that this is not a Rayleigh-Jeans approximation; with this definition, the true source flux can be recovered from T B sou 1V2 by inversion of the equation. Now, with the definition of antenna temperature, 20 or, as is more appropriate for our case, antenna temperature corrected for atmospheric absorption and hot spillover 21,22 1and port 2 emission2 T* A 1n2, which is given by…”