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Browsing by Author "Lancelot, J. P"

Browsing by Author "Lancelot, J. P"

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  • Development of an active-optics system for 27-inch thin mirror 
    Saxena, A. K; Lancelot, J. P; Samson, J. P (SPIE-The International Society for Optical Engineering, 1993-12)
    India is planning to build a large Optical/Infrared Telescope of 4 to 5 M in size. This telescope will adopt most of the features of the New Technology Telescope including active and adoptive optics corrections for achieving ...
  • Extended use of two crossed Babinet compensators for wavefront sensing in adaptive optics 
    Lancelot, J. P; Saxena, A. K (SPIE, 2010-12)
    An extended use of two crossed Babinet compensators as a wavefront sensor for adaptive optics applications is proposed. This method is based on the lateral shearing interferometry technique in two directions. A single ...
  • In-orbit Calibrations of the Ultraviolet Imaging Telescope 
    Tandon, S. N; Subramaniam, A; Girish, V; Postma, J; Sankarasubramanian, K; Sriram, S; Stalin, C. S; Mondal, Chayan; Sahu, S; Joseph, P; Hutchings, J; Ghosh, S. K; Barve, Indrajit V; George, K; Kamath, P. U; Kathiravan, S; Kumar, A; Lancelot, J. P; Leahy, D; Mahesh, P. K; Mohan, Rekhesh; Nagabhushana, S; Pati, A. K; Kameswara Rao, N; Sreedhar, Yuvraj Harsha; Sreekumar, P (IOP Publishing, 2017-09)
    The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375 mm telescopes: one for the far-ultraviolet (FUV) channel (1300–1800 Å), ...
  • In-orbit performance of UVIT on ASTROSAT 
    Subramaniam, A; Tandon, S. N; Hutchings, J; Ghosh, S. K; George, K; Girish, V; Kamath, P. U; Kathiravan, S; Kumar, Amit; Lancelot, J. P; Mahesh, P (SPIE--The International Society for Optical Engineering, 2016-07)
    We present the in-orbit performance and the first results from the ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and the ...
  • In-orbit performance of UVIT over the past 5 years 
    Ghosh, S. K; Joseph, P; Kumar, A; Postma, J; Stalin, C. S; Subramaniam, A; Tandon, S. N; Barve, Indrajit V; Devaraj, A; George, K; Girish, V; Hutchings, J. B; Kamath, P. U; Kathiravan, S; Lancelot, J. P; Leahy, D; Mahesh, P. K; Mohan, R; Nagabhushana, S; Pati, A. K; Kameswara Rao, N; Sankarasubramanian, K; Sreekumar, P; Sriram, S (Indian Academy of Sciences, 2021-10)
    Over the last 5 years, UVIT has completed observations of more than 500 proposals with ∼800 unique pointings. In addition, regular planned monitoring observations have been made and from their analysis various key parameters ...
  • Performance analysis of free space optical communication in open-atmospheric turbulence conditions with beam wandering compensation control 
    Anthonisamy, Arockia Bazil Raj; Durairaj, Padmavathi; Lancelot, J. P (IET, 2016-06-16)
    Among various atmospheric effects, beam wandering is the main cause for the major power loss in free space optical communication (FSOC) which cannot be resolved without incorporating the beam wandering compensation (BWC) ...
  • A Program for Testing Aspheric Schmidt Corrector Plate 
    Saxena, A. K; Lancelot, J. P (Indian Institute of Astrophysics, Bangalore, 1987)
    A null test for testing aspheric Schmidt corrector plate has been described. This paper gives a detailed procedure and a computer programe for computing optimum test parameters. A typical run of the program for testing a ...
  • Record of extended corona using colour video 
    Saxena, A. K; Samson, J. P. A; Lancelot, J. P (Indian Institute of Astrophysics, Bangalore, 1997)
    The entire event of the total solar eclipse of October 24 1995 was vediographed at our Kalpi camp. We have used SONY handy cam Video 8 Model No. CCD FX 280E PAL attached with 12x variable zoom lens. Partial eclipse was ...
  • Seasonal investigation on prediction accuracy of atmospheric turbulence strength with a new model at Punalkulam, Tamil Nadu 
    Bazil Raj, A. Arockia; Lancelot, J. P (Optical Society of America, 2016-04)
    Atmospheric parameters strongly affect the performance of free space optical communication systems when an optical wave is propagating through an inhomogeneous turbulence transmission medium. Developing models to get an ...
  • A Study of Inner Solar Corona during Total Solar Eclipse of October 24, 1995 
    Saxena, A. K; Cowsik, R; Lancelot, J. P; Samson, J. P. A; Bagare, S. P; Ismail, R (Indian Institute of Astrophysics, Bangalore, 1997)
    To study the inner corona during the total solar eclipse of October 24, 1995, an experiment was setup at Kalpi, the second location of the two IIA camps. Continuous broad record at regular interval at 40ms (TV rate) using ...
  • Theoretical fringe profiles with crossed Babinet compensators in testing concave aspheric surfaces 
    Saxena, A. K; Lancelot, J. P (Optical Society of America., 1982)
    This paper presents the theory for the use of crossed Babinet compensators in testing concave aspheric surfaces. Theoretical fringe profiles for a sphere and for an aspheric surface with primary aberration are shown. ...
  • Wavefront sensing and evaluation using two crossed Babinet Compensators 
    Saxena, A. K; Lancelot, J. P (SPIE-The International Society for Optical Engineering, 1990)
    The use of crossed Babinet Compensator (B. C.) combination as simple and effective device for wavefront sensing and evaluation has been described. This method can be utilized for on line evaluation of the wavefront or the ...

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