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Browsing by Author "Sankarasubramanian, K"

Browsing by Author "Sankarasubramanian, K"

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  • Additional calibration of the ultraviolet imaging telescope on board AstroSat 
    Tandon, S. N; Postma, J; Joseph, P; Devaraj, A; Subramaniam, A; Subramaniam, I. V; George, K; Ghosh, S. K; Girish, V; Hutchings, J. B; Kamath, P. U; Kathiravan, S; Kumar, A; Lancelo, J. P; Leahy, D; Mahesh, P. K; Mohan, R; Nagabhushana, S; Pati, A. K; Kameswara Rao, N; Sankarasubramanian, K; Sriram, S; Stalin, C. S (IOP Publishing, 2020-04)
    Results of the initial calibration of the Ultra-Violet Imaging Telescope (UVIT) were reported earlier by Tandon et al. The results reported earlier were based on the ground calibration as well as the first observations in ...
  • The Aditya-L1 mission of ISRO 
    Tripathi, Durgesh; Chakrabarty, D; Nandi, A; Prasad, B. R; Ramaprakash, A. N; Shaji, Nigar; Sankarasubramanian, K; Satheesh Thampi, R; Yadav, V. K (Cambridge University Press on behalf of International Astronomical Union, 2023)
    The Aditya-L1 is the first space-based solar observatory of the Indian Space Research Organization (ISRO). The spacecraft will carry seven payloads providing uninterrupted observations of the Sun from the first Lagrangian ...
  • Analysis of polarization introduced due to the telescope optics of the Thirty Meter Telescope 
    Ramya, M. Anche; Sen, A; Anupama, G. C; Sankarasubramanian, K; Skidmore, W (SPIE-The International Society for Optical Engineering, 2018-01)
    An analytical model has been developed to estimate the polarization effects, such as instrumental polarization (IP), crosstalk (CT), and depolarization, due to the optics of the Thirty Meter Telescope. These are estimated ...
  • AOTF-based spectro-polarimeter for observing Earth as an exoplanet 
    Jaiswal, Bhavesh; Singh, Swapnil; Jain, Anand; Sankarasubramanian, K; Nandi, Anuj (SPIE-Society of Photo-Optical Instrumentation Engineers, 2022-10)
    Earth is the only known habitable planet and it serves as a testbed to benchmark the observations of temperate and more Earth-like exoplanets. It is required to observe the diskintegrated signatures of Earth for a large ...
  • ASTROSAT mission 
    Singh, Kulinder Pal; Tandon, S. N; Agrawal, P. C; Antia, H. M; Manchanda, R. K; Yadav, J. S; Seetha, S; Ramadevi, M. C; Rao, A. R; Bhattacharya, D; Paul, B; Sreekumar, P; Bhattacharyya, S; Stewart, G. C; Hutchings, J; Subramaniam, A; Ghosh, S. K; Murthy, J; Pati, A. K; Kameswara Rao, N; Stalin, C. S; Girish, V; Sankarasubramanian, K; Vadawale, S; Bhalerao, V. B; Dewangan, G. C; Dedhia, D. K; Hingar, M. K; Katoch, T. B; Kothare, A. T; Mirza, I; Mukerjee, K; Shah, H; Shah, P; Mohan, Rekhesh; Sangal, A. K; Nagabhusana, S; Sriram, S; Malkar, J. P; Sreekumar, S; Abbey, A. F; Hansford, G. M; Beardmore, A. P; Sharma, M. R; Murthy, S; Kulkarni, R; Meena, G; Babu, V. C; Postma, J (SPIE--The International Society for Optical Engineering, 2014-07)
    ASTROSAT is India’s first astronomy satellite that will carry an array of instruments capable of simultaneous observations in a broad range of wavelengths: from the visible, near ultraviolet (NUV), far-UV (FUV), soft X-rays ...
  • Automated detection of coronal mass ejections in visible emission line coronagraph (VELC) on-board ADITYA-L1 
    Ritesh Patel; Amareswari, K; Pant, V; Banerjee, D; Sankarasubramanian, K (Cambridge University Press, 2018-02)
    An onboard automated coronal mass ejections (CMEs) detection algorithm has been developed for Visible Emission Line Coronagraph (VELC) onboard ADITYA-L1. The aim of this algorithm is to reduce the load on telemetry by ...
  • A CCD-based polarization interferometric technique for testing waveplates 
    Sankarasubramanian, K; Venkatakrishnan, P (Elsevier Science Ltd, 1998-02)
    A CCD-based polarization interferometric technique is developed to test waveplates. A Babinet compensator is used to produce interference fringes for polarized input and the retardance introduced by the waveplate when ...
  • Century long study of sunspot activity using the Kodaikanal white-light data 
    Amareswari, K; Sankarasubramanian, K; Ravindra, B (Cambridge University Press, 2018-02)
    Sunspots are the most obvious and high contrast observable feature of solar magnetic activity in the photosphere. The morphological and kinematic behaviour of sunspots on the solar surface need to be studied over a long ...
  • Characterizing Spectral Channels of Visible Emission Line Coronagraph of Aditya-L1 
    Ritesh Patel; Megha, A; Shrivastav, Arpit Kumar; Pant, V; Vishnu, M; Sankarasubramanian, K; Banerjee, D (Frontiers, 2021-06)
    Aditya-L1 is India’s first solar mission with the Visible Emission Line Coronagraph (VELC), which consists of three spectral channels taking high-resolution spectroscopic observations of the inner corona up to 1.5 Rʘ at ...
  • Coronal magnetic field measurements using forbidden emission lines 
    Megha, A; Sampoorna, M; Nagendra, K. N; Sankarasubramanian, K (Cambridge University Press, 2018-02)
    The polarization measurement of coronal forbidden emission lines is the most promising method of determining the direction of magnetic fields in the corona. A classical theory for the forbidden lines was presented in Megha ...
  • Diagnosing chromospheric magnetic field through simultaneous spectropolarimetry in Hα and Ca II 854.2 nm 
    Nagaraju, K; Sankarasubramanian, K; Rangarajan, K. E (Cambridge University Press, 2020)
    Measurement of magnetic field in this layer is challenging both from point of view of observations and interpretation of the data. We present in this work about spectropolarimetric observations of a pore, simultaneously ...
  • Dissecting star formation in the "Atoms-for-Peace" galaxy UVIT observations of the post-merger galaxy NGC7252 
    George, K; Joseph, P; Cote, P; Ghosh, S. K; Hutchings, J. B; Mohan, Rekhesh; Postma, J; Sankarasubramanian, K; Sreekumar, P; Stalin, C. S; Subramaniam, A; Tandon, S. N (EDP Sciences, 2018-06)
    Context. The tidal tails of post-merger galaxies exhibit ongoing star formation far from their disks. The study of such systems can be useful for our understanding of gas condensation in diverse environments. Aims. The ...
  • An efficient modulation scheme for dual beam polarimetry 
    Nagaraju, K; Ramesh, K. B; Sankarasubramanian, K; Rangarajan, K. E (Astronomical Society of India, 2007-09)
    An eight stage balanced modulation scheme for dual beam polarimetry is presented in this paper. The four Stokes parameters are weighted equally in all the eight stages of modulation resulting in total polarimetric efficiency ...
  • Elemental abundances in the solar corona as measured by the X-ray solar monitor onboard Chandrayaan-1 
    Narendranath, S; Sreekumar, P; Alha, L; Sankarasubramanian, K; Huovelin, J; Athiray, P. S (Springer, 2014-05)
    The X-ray Solar Monitor (XSM) on the Indian lunar mission Chandrayaan-1 was flown to complement lunar elemental abundance studies by the X-ray fluorescence experiment C1XS. XSM measured the ≈ 1.8 – 20 keV solar X-ray ...
  • Ellipsometry of Coelostat Coatings Using a Babinet Compensator: Simulation of the Experimental Accuracy 
    Sankarasubramanian, K; Venkatakrishnan, P (Kluwer Academic Publishers, 1996-08)
    The precise measurement of solar magnetic fields requires an accurate measurement of the Muller matrix of the optical components in the path of the light beam, which again requires a careful measurement of the optical ...
  • Estimation of polarization aberrations and its effect on the point spread function of the Thirty Meter Telescope 
    Ramya, M. Anche; Anupama, G. C; Sriram, S; Sankarasubramanian, K; Skidmore, W (SPIE--The International Society for Optical Engineering, 2018-07)
    The Thirty Meter Telescope (TMT) is a future generation telescope proposed to be located in Mauna Kea, Hawaii or in La Palma in the Canary Islands. The telescope will have a segmented primary and an inclined tertiary mirror. ...
  • The estimation of the instrumental polarization and crosstalk at the focus of the mid-infrared imaging system for the Thirty Meter Telescope 
    Ramya, M. Anche; Packham, Chris; Anupama, G. C; Sankarasubramanian, K; Maheswar, G; Manoj, P (SPIE--The International Society for Optical Engineering, 2018-07)
    The Thirty Meter Telescope (TMT) is a proposed future generation telescope which will be located on either Maunakea, Hawaii or La Palma in the Canary islands. A thermal-infrared (TIR) imager and spectrometer (MICHI) combined ...
  • Fast Iterative Techniques for Polarized Radiative Transfer in Spherically Symmetric Moving Media 
    Megha, A; Sampoorna, M; Nagendra, K. N; Anusha, L. S; Sankarasubramanian, K (IOP Publishing, 2020-11-01)
    For a more precise modeling of polarized spectral lines formed in extended and expanding stellar atmospheres, the solution of the radiative transfer equation for the Stokes vectors must be obtained in a spherical geometry ...
  • Hanle-Zeeman Scattering Matrix for Magnetic Dipole Transitions 
    Megha, A; Sampoorna, M; Nagendra, K. N; Sankarasubramanian, K (IOP Publishing, 2017-07)
    The polarization of the light that is scattered by the coronal ions is influenced by the anisotropic illumination from the photosphere and the magnetic field structuring in the solar corona. The properties of the coronal ...
  • The Horizontal Branch Population of NGC 1851 as Revealed by the Ultraviolet Imaging Telescope (UVIT) 
    Subramaniam, A; Snehalata Sahu; Postma, J; Cote, Patrick; Hutchings, J. B; Darukhanawalla, N; Chung, Chul; Tandon, S. N; Kameswara Rao, N; George, K; Ghosh, S. K; Girish, V; Murthy, J; Mohan, Rekhesh; Murthy, J; Pati, A. K; Sankarasubramanian, K; Stalin, C. S; Choudhury, S (IOP Publishing, 2017-12)
    The Horizontal Branch Population of NGC 1851 as Revealed by the Ultraviolet Imaging Telescope ( UVIT ) Annapurni Subramaniam 1 , Snehalata Sahu 1 , Joseph E. Postma 2 , Patrick Côté 3 , J. B. Hutchings 3 , ...

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