IIA Institutional Repository: Recent submissions

  • Solar radiation in the far ultraviolet and some related geophysical phenomena 
    Das, A. K (Manager of Publications Civil Lines Delhi, 1954-12)
    It has been known for a long time that apart from the visible and heat radiations of Photospheric origin there are other radiations which emanate from the sun and produce notable effects on the earth's atmosphere and on ...
  • A precision direct-reading spectrophotometer 
    Narayan, A. L; Ananthasubrahmanyam, C. K (Calcutta University Press, 1940-10)
    The experimental errors inherent in photographic photometry are discussed and a direct reading spectrophotometer for the visible especially adapted to the study of line, contour and absorption and fluorescence spectra is ...
  • Prominence activity (1905–1952) 
    Ananthakrishnan, R (Indian Academy of Sciences, 1954-08)
  • Intensity distribution and contrast of the solar EUV network 
    Raju, K. P (Springer, 2010-03)
    Intensity distributions of the EUV network and the cell interior in the solar atmosphere have been obtained in fourteen emission lines from Solar and Heliospheric Observatory (SOHO)/Coronal Diagnostic Spectrometer (CDS) ...
  • On the flare induced high-frequency global waves in the sun 
    Kumar, B; Mathur, S; García, R. A; Venkatakrishnan, P (Institute of Physics, 2010-03-01)
    Recently, Karoff & Kjeldsen presented evidence of strong correlation between the energy in the high-frequency part (5.3 < ν < 8.3 mHz) of the acoustic spectrum of the Sun and the solar X-ray flux. They have used disk-integrated ...
  • Spectrophotometric study of sunspots 
    Ananthakrishnan, R (Indian Academy of Sciences, 1953-02)
  • Sun-spots and magnetic storms during the last week of March, 1940 
    Salaruddin, MD; Ananthasubrahmanyam, C. K (Indian Science News Association, 1940)
  • Recurrence tendency of geomagnetic activity during the current sunspot minimum 
    Naqvi, Ali. M; Bhargava, B. N (Manager of Publications Civil Lines Delhi, 1954-12)
    Geomagnetic Activity during the three year period June 1950-June 1953, has been analysed and found to consist mainly of two very long sequences of recurrent (27-day period) moderate geomagnetic storms. During the three ...
  • Further investigation of the arc spectrum of arsenic 
    Rao, A. S (Institute of Physics, 1932-09)
    By photographing the spectrum of arsenic by the method of the hollowcathode discharge in helium and in neon about 100 new lines have been recorded. In the light of the experimental data, the analysis of As I published by ...
  • Centroid detection by Gaussian pattern matching in adaptive optics 
    Vyas, A; Roopashree, M. B; Prasad, B. R (Foundation of Computer Science, 2010)
    Shack Hartmann wavefront sensor is a two dimensional array of lenslets which is used to detect the incoming phase distorted wavefront through local tilt measurements made by recording the spot pattern near the focal plane. ...
  • Real-time wind speed measurement using wavefront sensor data 
    Roopashree, M. B; Vyas, A; Prasad, B. R (SPIE-The International Society for Optical Engineering, 2010-02)
    Real-time measurement of effective wind speed helps in continuous monitoring of the temporal bandwidth in adaptive optics systems. In this paper, we propose a simple and efficient method for estimating wind speed from ...
  • Improved iteratively weighted centroiding for accurate spot detection in laser guide star based Shack Hartmann sensor 
    Vyas, A; Roopashree, M. B; Prasad, B. R (SPIE-The International Society for Optical Engineering, 2010-02)
    A hybrid centroiding technique involving Iteratively Weighted Center of Gravity (IWCoG) algorithm and correlation technique for a Laser Guide Star (LGS) based Shack Hartmann wavefront sensor is proposed. A simple method ...
  • A search for unrecognized carbon-enhanced metal-poor stars in the galaxy 
    Placco, V. M; Kennedy, C. R; Rossi, S; Beers, T. C; Lee, Y. S; Christlieb, N; Sivarani, T; Reimers, D; Wisotzki, L (Institute of Physics, 2010-03)
    We have developed a new procedure to search for carbon-enhanced metal-poor (CEMP) stars from the Hamburg/ESO (HES) prism-survey plates. This method employs an extended line index for the CH G band, which we demonstrate to ...
  • SDSS J123813.73-033933.0: a cataclysmic variable evolved beyond the period minimum 
    Aviles, A; Zharikov, S; Tovmassian, G; Michel, R; Tapia, M; Roth, M; Neustroev, V; Zurita, C; Andreev, M; Sergeev, A; Pavlenko, E; Tsymbal, V; Anupama, G. C; Kamath, U. S; Sahu, D. K (Institute of Physics, 2010-03)
    We present infrared JHK photometry of the cataclysmic variable (CV) SDSS J123813.73 – 033933.0 and analyze it along with optical spectroscopy, demonstrating that the binary system is most probably comprised of a massive ...
  • CCD time-series photometry of the globular cluster NGC 5053: RR Lyrae, Blue Stragglers and SX Phoenicis stars revisited 
    Arellano Ferro, A; Giridhar, S; Bramich, D. M (Blackwell Publishing, 2010-02)
    We report the results of CCD V, r and I time-series photometry of the globular cluster NGC 5053. New times of maximum light are given for the eight known RR Lyrae stars in the field of our images, and their periods are ...
  • Activity dependence of solar supergranular fractal dimension 
    Paniveni, U; Krishan, V; Singh, J; Srikanth, R (Blackwell Publishing, 2010-02)
    We study the complexity of supergranular cells using the intensity patterns obtained at the Kodaikanal Solar Observatory during the solar maximum. Our data consist of visually identified supergranular cells, from which a ...
  • PDS microdensitometer at Indian Institute of Astrophysics 
    Sagar, R; Srinivasan, R (Tata Institute of Fundamental Research, 1988)
  • Image processing facilities at Vainu Bappu observatory 
    Giridhar, S; Bhattacharyya, J. C; Kutty, K. N (Tata Institute of Fundamental Research, 1988)
    Need for application of Image processing techniques in astronomical studies in optical wavelengths and special advantages accruing thereby are discussed. The paper describes various image processing facilities that are ...
  • Differential rotation of solar features and its variation as deduced from the "shock-transition model" of the solar cycle 
    Gokhale, M. H (Indian Institute of Astrophysics, 1979-11)
    From the topology of the two families of flux tubes in the shock-transition model of the solar cycle we predict the general nature of the differential rotation of: (i) sunspots and the small scale emission features in ...
  • The astronomical seeing at Kavalur. 
    Bappu, M. K. V; Mohin, S; Unnikrishnan, K. G (Indian Institute of Astrophysics, 1978)
    A summary of observing conditions at Kavalur Observatory is p0resented. These related to spectroscopic and photometric observations and to seeing as evaluated at the 102cm telescope. Nearly fifty percent of nights on which ...

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