Abstract


  IMAGING SPECTRO-POLARIMETER FOR MULTI APPLICATION SOLAR TELESCOPE (MAST): PRELIMINARY RESULTS OBTAINED IN THE PHOTOSPHERIC LINE FE I 617.3 NM

  A. Tiwary, Udaipur Solar Observatory, atiwary@prl.res.in
  S. Mathew, Udaipur Solar Observatory, Physical Research Laboratory, shibu@prl.res.in
  A. Bayanna, Udaipur Solar Observatory, Physical Research Laboratory, bayanna@prl.res.in
  R. Yadav, Udaipur Solar Observatory, Physical Research Laboratory, rahuly@prl.res.in

Multi-Application Solar Telescope (MAST) is an off-axis Gregorian telescope of 50 cm clear aperture situated on an island in the Fateh Sagar lake at Udaipur Solar Observatory (USO). An Imaging Spectro-polarimeter has been developed at USO as a back-end instrument of MAST for measuring the magnetic field in the photosphere and chromospheres at two different wavelengths. The system consists of a narrow-band imager and a polarimeter. Narrow-band imager uses two lithium niobate Fabry-Perot etalons in tandem with a blocking filter for spectral analysis and the polarimeter has two Liquid Crystal Variable Retarder (LCVR) and a Glan-Thompson polarizer for polarization analysis. The instrument has been calibrated for the solar spectral lines Fe I 617.3 nm and Ca II 854.2 nm. Recently, we have obtained spectropolarimetric data of an active region in the photospheric line Fe I 617.3 nm. This data is inverted using an inversion technique based on ME atmosphere model and preliminary results will be presented here.