School Colloquia Series - Daniel Cotton - New Frontiers in Astronomical Polarimetry
Speaker: Dr Daniel Cotton
Polarimetry is a technique for measuring the orientation of photon oscillations. The polarisation of light is – along with colour (spectroscopy), intensity (photometry) and position (astrometry) – one of only four properties we can observe in astronomy. Of the four, polarimetry is the most under-utilised. At the precision of the previous generation of instrumentation (parts-per-ten-thousand) most starlight is unpolarised. So at the end of the last century the utility of optical polarimetry was largely limited to studying the dust in far-off space, stars with extreme magnetic fields, or material external to stars that scattered starlight.