Fabry-Perot Interferometric Observations of the Solar Corona in the Green Line

Abstract

An imaging Fabry-Perot interferometer was designed and used for coronal observations in the green line (FeXIV) 5303 Armstrong. The observations were carried our at Nim Ka Thana, Rajasthan, India during the total solar exlipse of 1995 October 24. A dielectric coated Fabry-Perot etalon with 92% reflectivity and spacing 350 micrometer was used to obtain the interference fringes. A liquid nitrogen cooled Photometrics CCD served as the detector. The green line emission was found to be extremely weak and restricted to the eastern and western limbs of the Sun. Emission line profiles were obtained at a few coronal locations. The average width was found to be 1.6 Armstrong indicative of the presence of large turbulent velocities (49 kms(-1)). One of the line peofiles, showed line splitting, possibly due to mass motion in the corona.