IIA Institutional Repository: Recent submissions

  • Intensity Fluctuations in the H-alpha line caused by Chromospheric mottling 
    Bappu, M. K. V (IETE, 1964)
    Spectra of the H-alpha line obtained with high dispersion and high spatial resolution are used to study some of the characteristics of chromospheric mottling on the solar disk. The fluctuations in intensity, indicated by ...
  • Radio Star Scintillations in Equatorial Region 
    Bhargava, B. N (IETE, 1964)
    The technique of obtaining information on ionospheric irrgularities by observing scintillation of signal from discrete sources of radio noise is described. Work on scintillation carried out at a few equatorial stations in ...
  • A Note on the Equatorial Electrojet 
    Bhargava, B. N (Indian Meteorological Department, 1964)
  • Spatial, Seasonal and Solar Cycle characteristics of the Loss Coefficient in Ionospheric F-region 
    Bhargava, B. N; Subrahmanyan, R. V (Indian Meteorological Department, 1964)
    Evaluations of loss coefficient at several fixed heights of ionospheric F-region by a comparatively simple method have been shown to yeild reasonable values. Seasonal characterstics of the loss coefficient have been obtained ...
  • Cusps and Distortions in Ionospheric Fl-layer observed over Kodaikanal 
    Sankaran, K. S (Indian Meteorological Department, 1964)
    A special study of cusps and distortions in Fl-layers traces has been made from ionograms obtained at Kodaikanal during a period of about half a solar cycle. Two differnet types of disturbance have been noticed. The first ...
  • Movements in the F region of the Ionosphere during Solar Eclipses 
    Bhargava, B. N; Subrahmanyan, R. V (Indian Meteorological Department, 1960)
    F layer ionospheric data collected during the partial solar eclipses of 20 June and 14 December 1955 have been analysed. In order to study the effects of the eclipses at several heights, the electron density height profiles ...
  • The influence of disturbed conditions and increased solar activity on geomagnetic distortion of the equatorial inonospheric F2 region 
    Bhargava, B. N; Subrahmanyan, R. V (Indian National Science Academy, 1962)
    The principal diurnal anomalies in the maximum electron density of ionospheric F2 layer over Kodaikanal are discussed. From an analysis of data obtained over half a solar cycle, it has been found that the phenomena of rapid ...
  • A study of the Pre-Sunrise F-layer stratification at Kodaikanal 
    Bhargava, B. N; Subrahmanyan, R. V (Indian National Science Academy, 1961)
    The pre-sunrise phenomenon of a rapid drop in the maximum ionic density of F-layer followed by an increase in the semi-thickness and height of the layer and stratification is described. The phenomenon, which is found to ...
  • Design and Performance of V.H.F. receiving equipment for reception of extremely weak signals of solar and Galactic origin in the metre wavelength region 
    Bhargava, B. N; Jayarajan, A. P (IETE, 1960)
    Three V.H.F receivers of high gain stability and low internal noise designed and constructed at the Kodaikanal Observatory are described. The receivers which operate at 1 1/2, 3 and 5 meter wavelengths are being used for ...
  • The Flare of 1957 September 19 
    Jayanthan, R (Observatory, 1959)
  • Tidally affected galaxies modelled as Maclaurin spheroids 
    Som Sunder, G; Kochhar, R. K; Alladin, S. M (Astronomical Society of Indian, 1989-12)
    Tensor virial equations and impulse approximation are used to study the tidal transfer of energy and angular momentum to a test galaxy, modeled as a Maclaurin spheroid. It is shown that the fractional increase in kinetic ...
  • Short Note - a Solar Flare Event in CAII K on 1989 March 9 
    Uddin, W; Joshi, A (Astronomical Society of Indian, 1989-12)
  • Photographic astrometry of Comet Halley 
    Ballabh, G. M; Kilambi, G. C; Sanwal, N. B; Sreedhar Rao, S; Swaminathan, R; Raghavender Rao, C (Astronomical Society of Indian, 1989-12)
    The 20-cm astrograph of the Nizamiah and Japal-Rangapur Observatoies in India was used to obtain photographic plates of Comet Halley before and after perihelion during the 1985-1986 apparition. The images are reduced and ...
  • The long period spectroscopic binary HR 1176 
    Raghavender Rao, C; Abhyankar, K. D (Astronomical Society of Indian, 1989-12)
    Radial velocity measurements of the long-period spectroscopic binary HR 1176 are obtained from spectrograms made with a 1.22-m telescope at Japal-Rangapur Observatory in India. The spectral line and radial velocity ...
  • Yake effects in various telescope mirrors 
    Gupta, K. G (Astronomical Society of Indian, 1989-09)
    The yake effect in the 56 cm and the 38 cm pyrex mirrors of the Uttar Pradesh State Observatory is described. Similar effects elsewhere are also discussed.
  • Optical depth towards the nucleus of Halley's comet 
    Shah, G. A (Astronomical Society of Indian, 1989-09)
    A new relation between the nuclear radius and the optical depth toward the nucleus of Comet Halley has been derived on the basis of the radial variation of the effective area of the grains along the Giotto trajectory in ...
  • Narrow band photometry of Comet Halley in the emission bands and the continuum 
    Babu, G. S. D; Nathan, J. S; Rajamohan, R; Sivaraman, K. R (Astronomical Society of Indian, 1989-09)
    IHW filter photometry of Comet Halley was carried out on seven nights during pre-perihelion period and on six nights during post-perihelion period, using the 40-cm telescope at the Vainu Bappu Observatory, Kavalur, as a ...
  • Transient activity in the loop prominence system of a flare active region 
    Bagare, S. P; Nagabhushana, B. S; Aleem, P. S. M (Astronomical Society of Indian, 1989-09)
    Solar limb observations of the activity in a loop prominence system associated with an active region were obtained on February 2, 1984. The activity was observed for a total duration of over seven hours of which the maximum ...
  • Polarimetric study of the RV Tauri star AC Herculis 
    Raveendran, A. V; Kameswara Rao, N; Anandaram, M. N (Astronomical Society of Indian, 1989-09)
    BVRI polarimetry of AC Her shows that the wavelength dependence of polarization is weak with a marginal increase towards blue and that the position angle is nearly independent of wavelength. It is argued that the interstellar ...
  • Observing conditions for optical astronomy at Leh 
    Singh, J; Bhattacharyya, J. C; Babu, G. S. D; Ashoka, B. N; Appakutty, M; Rangarajan, K. E; Kutty, K. N; Moorthy, V; Selvakumar, G; Michael, P; Muniyandi, A; Gabriel, F (Astronomical Society of India, 1989-09)
    The sky and atmospheric conditions at Leh have been monitored since 1984 with a view to determining its suitability as a site for a high-altitude observatory. During May-November, 1987, relative humidity and other parameters ...

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