Publications of Astronomical Society of India: Recent submissions

  • Fourier smoothing of digital photographic spectra 
    Anupama, G. C (Astronomical Society of India, 1990-03)
    Fourier methods of smoothing one-dimensional data are discussed with particular reference to digital photographic spectra. Data smoothed using lowpass filters with different cut-off frequencies are intercompared. A method ...
  • On the chronology of Hindu astronomy 
    Rana, N. C (Astronomical Society of India, 1990-03)
    An estimate for the probable age of the Hindu astronomy is made here from a reference to the exact longitude of the so-called exaltation of Mars. If it is interpreted as the location of the perihelion of the orbit of Mars ...
  • A high-speed two-star photometer 
    Venkat Rao, G (Astronomical Society of India, 1990-03)
    Design and performance of a high-speed two-star photometer are presented in this paper. It is an ideal instrument for investigations of time variations of variable stars
  • On ionized molecules in the solar atmosphere 
    Sinha, K; Tripathi, B. M (Astronomical Society of India, 1990-03)
    The partial pressures of 20 ionic molecular species are reported for standard facular, photospheric, and sunspot model atmospheres with a view to picking up ionized molecules for a possible identification in the solar ...
  • Effects of dust on equivalent widths of spectral lines formed in expanding spherically symmetric shells 
    Peraiah, A; Ingalgi, M. F (Astronomical Society of India, 1990-03)
    A study is made of the effects of the presence of dust and radial expansion of the spherical shells around stars on the equivalent widths of the lines formed in such shells. A non-LTE, two-level atom approximation is ...
  • Some further characteristics of observing conditions at Leh 
    Singh, J; Bhattacharyya, J. C; Babu, G. S. D; Appakutty, M; Kuppuswamy, K; Moorthy, V; Devendran, P; Velu, C; Sivakumar, R (Astronomical Society of India, 1990-03)
    The sky conditions were monitored and duration of photometric and spectroscopic hours determined on 198 nights during the period September 1984 to October 1986. Observations were continued from May till November 1987 and ...
  • Atmospheric extinction measurements at Leh in near infrared bands 
    Bhattacharyya, J. C; Scaria, K. K; Singh, J; Babu, G. S. D; Muraleedharan Nair, R; Sivaraman, K. R (Astronomical Society of Indian, 1990-03)
    Site survey observations to determine the extinction in the IR bands were carried out at Leh. Mean extinction coefficients obtained from 'two nights' observations in J, H, and K bands are k(J) = 0.05 + or - 0.01; k(H) = ...
  • 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 ...
  • Emission line diagnostics for a coronal condensation 
    Raju, P. K (Astronomical Society of Indian, 1989-09)
    Theoretical line emission rates for the coronal ions Fe X, Fe XI, FE XIII, Fe XIV, Ca XII, Ca XIII, and Ca XV, have been used to obtain various line intensity ratios as a function of electron density and electron temperature. ...
  • Development of a stellar SPOT model 
    Nagar, P (Astronomical Society of Indian, 1989-09)
    A spectroscopic spot model has been developed incorporating spot magnetic fields. It is shown that the presence of spot magnetic field makes a noticeable effect on the shape of spectral lines
  • The Moon Illusion and the Height of the Sky 
    Abhyankar, K. D (Astronomical Society of Indian, 1989-09)
    It is shown that the apparently flattened celestial vault can be represented by a geocentric sphere at a height of 3000-4000 km above the surface of the earth. It is also argued that our eye estimates the distance to this ...

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