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Browsing by Author "Saha, S. K"

Browsing by Author "Saha, S. K"

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  • Aperture Synthesis at Optical Wavelengths 
    Saha, S. K (Department of Applied Optics and photonics, University of Calcutta, 2011)
    Optical stellar interferometers have demonstrated milli-arcsecond resolution with few apertures spaced tens of meters apart. Results from the area of stellar angular diameters with implications for emergent fluxes, ...
  • Aperture synthesis in optical astronomy; the current status 
    Saha, S. K (Invertis, Inc, 2007)
    A milestone in observational astronomy was achieved when the interferometric fringes of Lyrae (Vega) in the visible band were obtained in July 1974, by A. Labeyrie from an interferometer, called Interferometre a deux ...
  • Astrophotography with high angular and temporal resolution: Preliminary results from the Kavalur Experiments 
    Saha, S. K; Venkatakrishnan, P; Jayarajan, A. P; Jayavel, N (Indian Academy of Sciences, 1987-10)
    Preliminary results in the form of photographs obtained with high angular (≈ 0.”1) and temporal ( ≈ 33 to 6ms) resolutions using 1-m reflector at the Vainu Bappu Observatory in Kavalur are presented. These results demonstrate ...
  • Auto-correlation of Binary stars 
    Saha, S. K; Maitra, D (Indian Association for the Cultivation of Science, 2001)
    Speckle interferometric technique is used to record a series of short exposure images of several close binary stars with sub-arcsecond separation through a narrow band filter centred at H$\alpha$ at the Cassegrain focus ...
  • Blind iterative deconvolution of binary star images 
    Saha, S. K; Venkatakrishnan, P (Astronomical Society of India, 1997)
    The technique of Blind Iterative De-convolution (BID) was used to remove the atmospherically induced point spread function (PSF) from short exposure images of two binary stars, HR 5138 and 5747 obtained at the cassegrain ...
  • Computationally efficient method for retrieval of atmospherically distorted astronomical images 
    Surya, A; Saha, S. K (Springer, 2014-12)
    Speckle Imaging based on triple correlation is a very efficient image reconstruction technique which is used to retrieve Fourier phase information of the object in presence of atmospheric turbulence. We have developed both ...
  • Design of a mammary gland specific gamma imaging system (MSGIS) 
    Sarbajit, P; Bhattacharjee, T; Saha, S. K (Macmillan Publishers India Ltd., 2009)
    In conventional X-ray mammography, the presences of a small lesion/tumor at the early stage of cancer are not definitely detected because of the complex anatomy of the breast tissues. On the other hand, the low resolution ...
  • Detectors for the astronomical applications 
    Saha, S. K (Macmillan Publishers India Ltd., 2009)
    Astronomical observations are dependent on focal-plane instruments, and detectors continue to play a key role. The detector technology is evolving rather fast with the large-format CMOS and CCD array mosaics, electron-multiplying ...
  • Development of a Speckle Interferometer and the Measurement of Fried's Parameter (ro) at the Telescope Site 
    Saha, S. K; Sudheendra, G; Chandra, A. U; Chinnappan, V (Kluwer Academic Publishers, 1999)
    A new optical speckle interferometer for use at the 2.34 meter Vainu Bappu Telescope (VBT), at Vainu Bappu Observatory (VBO), Kavalur, India, has been designed and developed. Provisions have been made for observation both ...
  • Diffraction limited imaging with large and moderate telescopes 
    Saha, S. K (World Scientific Publishing, 2007)
    This book deals with the fundamentals of wave optics, polarization, interference, diffraction, imaging, and the origin, properties, and optical effects of turbulence in the Earth's atmosphere. Techniques developed during ...
  • Emerging trends of optical interferometry in astronomy 
    Saha, S. K (Astronomical Society of India, 1999)
    The current status of the high spatial resolution imaging interferometry in optical astronomy is reviewed in the light of theoretical explanation, as well as of experimental constraints that exist in the present day ...
  • FPGA Based ASM implementation for CCD Camera Controller 
    Srinivasan, R; Anupama, K; Suneeta; Saha, S. K; Rao, A (MacMillan Publishers Ind. Ltd, 2009)
    A general purpose CCD controller that can address any CCD, has been developed at the Indian Institute of Astrophysics. It is based on a Digital Signal Processor (DSP) chip, Motorola DSP 56002 for implementing essential ...
  • High resolution imaging by employing passive and active approaches 
    Saha, S. K (Anita Publications, 2002)
  • High resolution imaging: detectors and applications 
    Saha, S. K (Pan Stanford publishing, 2015)
    Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in ...
  • Hypertelescope Approach: A Novel Method for Imaging of Stellar Objects 
    Saha, S. K (Optical Society of India, 2011)
    The diffraction limited phase retrieval of a degraded image is an important subject that is being implemented in other branches of physics too, for example, electron microscopy, wavefront sensing, and crystallography. A ...
  • Hypertelescope imaging 
    Saha, S. K (Anita Publications, 2011-03)
    Single aperture interferometry by means of speckle imaging has made inroads in several important fields in astrophysics. In recent years, the adaptive optics system at the telescope has produced spectacular results. ...
  • Intensified CCD Camera Based Remote Guiding Unit for VBT and Observation of Speckles with ICCD 
    Chinnappan, V; Saha, S. K; Faseehana (Indian Institute of Astrophysics, Bangalore, 1991)
    For successful observations in any telescope, guiding becomes important. On 2.34 m Telescope at Vainu Bappu Observatory, Kavalur, a remote guiding system is assembled using Intensified CCD camera and a PC based image ...
  • Laser guide artificial star for high resolution imaging 
    Saha, S. K (Indian Association for the Cultivation of Science, 2006)
    A large telescope encodes the information about the source, but unable to get the di raction-limited informations. Due to the inhomogeneity of the propagating medium that carries the light to the Earth's surface, the ...
  • Micro-fluctuations of fried's parameter (ro) 
    Saha, S. K; Yeswanth, L (Anita Publications, 2004)
    The atmospheric coherence is a highly variable parameter depending upon the high velocity wind. The size of the atmospheric coherence length widely known as, Fried's parameter, ro, has been computed during night at the ...
  • Modern optical astronomy: technology and impact of interferometry 
    Saha, S. K (The American Physical Society, 2002-04)
    The present ``state of the art'' and the path to future progress in high-spatial-resolution imaging interferometry is reviewed. The review begins with a treatment of the fundamentals of stellar optical interferometry, the ...

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