IIAP Publications: Recent submissions

  • After the fall: from Adam and Eve to apples and elevators 
    Vishveshwara, C. V (Inter-University Center for Astronomy and Astrophysics, 1998)
  • Performance of centroiding algorithms at low light level conditions in adaptive optics 
    Vyas, A; Roopashree, M. B; Prasad, B. R (The Institute of Electrical and Electronics Engineers, Inc, 2009)
    The performance metrics of different centroiding algorithms at low light level conditions were optimized in the case of a Shack Hartmann Sensor (SHS) for efficient performance of the adaptive optics system. For short ...
  • Ionospheric total electron content and slab-thickness at low latitudes in Indian zone 
    Rastogi, R. G; Iyer, K. N; Sharma, R. P (Indian Academy of Sciences, 1977-06)
    Observations of Faraday rotation of beacon signals from low orbiting satellite BE-B recorded at one station near the dip equator (Kodaikanal, dip 3·4° N) and at another station near the peak of the equatorial anomaly ...
  • The Evershed effect as we understand it today 
    Rajaguru, S. P (Indian Academy of Sciences, 2009-11)
    Following a description of the Evershed effect as observed by John Evershed in 1909 at the Kodaikanal Solar Observatory, we discuss the evolution of our scientific understanding that accompanied the development of the ...
  • Range and frequency spread-F at Kodaikanal 
    Sastri, J. H; Sasidharan, K; Subramanyam, V; Srirama Rao, M (European Geophysical Society, 1979-09)
    Using ionogram data at Kodaikanal (geomagnetic lat. 06 deg N, Dip 3.5 deg N) over a seven year period, Jan. 1957-Dec. 1963, a study is made of the seasonal and sunspot cycle variations in the nocturnal occurrence of amplitude ...
  • Ionosphere scintillations associated with features of equatorial ionosphere 
    Chandra, H; Vats, H. O; Sethia, G; Deshpande, M. R; Rastogi, R. G; Sastri, J. H; Murthy, B. S (European Geophysical Society, 1979-09)
    Amplitude scintillations of radio beacons aboard the ATS-6 satellite on 40 MHz, 140 MHz and 360 MHz recorded during the ATS-6 phase II at an equatorial station Ootacamund (dip 4 deg N) and the ionograms at a nearby station ...
  • Gravitational searchlight and its astrophysical applications 
    Chitre, S. M; Narlikar, J. V; Kapoor, R. C (Nature Publishing Group, 1974-12)
    Attention is given to an interesting effect associated with light emitted in the forward direction by a source circulating in an equatorial plane around a highly collapsed object or a black hole. The emitted light received ...
  • Effect of steady flow and Newton's cooling on the propagation and damping of small-amplitude prominence plasma oscillations 
    Singh, K. A. P; Dwivedi, B. N (Cambridge University Press, 2009-08)
    In study the propagation and damping of small-amplitude prominence oscillations invoking steady flow and radiative losses due to Newton's cooling with constant relaxation time. We find that the strength of steady flow has ...
  • Solar-like oscillations in HD 181420: data analysis of 156 days of CoRoT data 
    Barban, C; Deheuvels, S; Baudin, F; Appourchaux, T; Auvergne, M; Ballot, J; Boumier, P; Chaplin, W. J; Garcia, R. A; Gaulme, P; Michel, E; Mosser, B; Regulo, C; Roxburgh, I. W; Verner, G; Baglin, A; Catala, C; Samadi, R; Bruntt, H; Elsworth, Y; Mathur, S (EDP Sciences, 2009-10)
    Context. The estimate of solar-like oscillation properties, such as their frequencies, amplitudes and lifetimes, is challenging because of their low amplitudes and will benefit from long and uninterrupted observing runs. ...
  • Investigations of the pre-deep impact morphology of the dust coma of comet tempel 1 
    Vasundhara, R (Elsevier, 2009-11)
    The pre-Deep Impact images of Comet Tempel-1 obtained at the Indian Astronomical Observatory are used to investigate the morphology of the dust coma of the comet. We show that the trajectory of a cometary grain under the ...
  • Simultaneous MITSuME g'RCIC monitoring of S5 0716+714 
    Stalin, C. S; Kawabata, K. S; Uemura, M; Yoshida, M; Kawai, N; Yanagisawa, K; Shimizu, Y; Kuroda, D; Nagayama, S; Toda, H (Blackwell Publishing, 2009-11)
    We present the results of our intra-night optical flux monitoring observations of S5 0716+714 done simultaneously in g',RC and IC filters. The observations were done using the Multicolor Imaging Telescopes for Survey and ...
  • Optical and x-ray observations of M31N 2007-12b: an extragalactic recurrent nova with a detected progenitor? 
    Bode, M. F; Darnley, M. J; Shafter, A. W; Page, K. L; Smirnova, O; Anupama, G. C; Hilton, T (The American Astronomical Society, 2009-11)
    We report combined optical and X-ray observations of nova M31N 2007-12b. Optical spectroscopy obtained 5 days after the 2007 December outburst shows evidence of very high ejection velocities (FWHM Hα sime 4500 km s-1). In ...
  • Optical linear polarization in ultra cool dwarfs: A tool to probe dust in the ultra cool dwarf atmospheres 
    Tata, R; Martin, E. L; Sengupta, S; Phan-Bao, N; Zapatero Osorio, M. R; Bouy, H (European Space Agency, 2009-12)
    Aims.Recent studies have detected linear polarization in L dwarfs in the optical I band. Theoretical models have been developed to explain this polarization. These models predict higher polarization at shorter wavelengths. ...
  • Prediction of wavefronts in adaptive optics to reduce servo lag errors using data mining 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    Servo lag errors in adaptive optics lead to inaccurate compensation of wavefront distortions. An attempt has been made to predict future wavefronts using data mining on wavefronts of the immediate past to reduce these ...
  • Phase characteristics of reflecting and transmitting type twisted nematic spatial light modulators 
    Roopashree, M. B; Vyas, A; Banyal, R. K; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    The phase characteristics of reflecting and transmitting type twisted nematic liquid crystal based Spatial Light Modulators (SLMs) were measured using interferometry. Device parameters like contrast, brightness, input ...
  • Performance analysis of fourier and vector matrix multiply methods for phase reconstruction from slope measurements 
    Roopashree, M. B; Vyas, A; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    The accuracy of wavefront reconstruction from discrete slope measurements depends on the sampling geometry, coherence length of the incoming wavefronts, wavefront sensor specifications and the accuracy of the reconstruction ...
  • Effective coherence length estimation of optical wavefronts 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    In adaptive optics, the measurement of spatial coherence length helps in deciding the optimum design parameters of a Shack Hartmann Sensor (SHS). Two methods of estimating the spatial coherence length of optical wavefronts ...
  • Digital long focal length lenslet array using spatial light modulator 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    Under a thin lens and paraxial approximation, the phase transformation function of a lens was simulated on a Liquid Crystal (LC) based Spatial Light Modulator (SLM). The properties of an array of such lenses simulated ...
  • Measurement of gradient index profiles by babinet fringe analysis 
    Pandya, T. P; Saxena, A. K (American Institute of Physics, 1979-03)
    A theory for determining one-dimensional ray deflections with the help of distorted Babinet fringes has been developed. An approach for investigating two-dimensional ray deflections has been presented. Applications of the ...
  • Travelling wave solutions for inhomogeneous acoustic gravity waves 
    Das, G. C (Springer, 1979-09)
    Traveling wave solutions to an inhomogeneous hyperbolic equation for acoustic gravity waves in an isothermal atmosphere are investigated. A traveling wave solution of rank one is obtained in terms of a single ordinary ...

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