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Browsing by Author "Raveendran, A. V"

Browsing by Author "Raveendran, A. V"

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  • A D. C. Amplifier for Photoelectric Photometry 
    Raveendran, A. V; Mohin, S (Indian Institute of Astrophysics, Bangalore, 1987)
    We describe the construction and discuss the performance of a d.c. amplifier which was installed at the 34-cm telescope of Vainu Bappu Observatory in 1987 January and since then extensively used for variable star photometry.
  • Detection of Short-Period Coronal Oscillations during the Total Solar Eclipse of 24 October, 1995 
    Singh, J; Cowsik, R; Raveendran, A. V; Bagare, S. P; Saxena, A. K; Sundararaman, K; Krishan, V; Naidu, N; Samson, J. P. A; Gabriel, F (Springer, 1997-02)
    An experiment to search for short-period oscillations in the solar corona was conducted during the total solar eclipse of 1995 October 24 at Kalpi, India. The intensity in the continuum, centred around 5500 Å and with a ...
  • Dramatic Changes in the Polarization of AR Pup 
    Raveendran, A. V; Deshpande, M. R; Kameswara Rao, N; Joshi, U. C; Kuleshrestha, A. K (Konkoly Observatory, 1985-04-25)
  • Dust envelopes around RV Tauri stars 
    Raveendran, A. V (The Royal Astronomical Society, 1989-06)
    In the IRAS (12)-(25), (25)-(60) color-color diagram, RV Tauri stars are found to populate cooler temperature regions, distinctly different from those occupied by the oxygen and carbon Miras. The IRAS fluxes are consistent ...
  • Evolution of starspot regions in DM UMa 
    Mohin, S; Raveendran, A. V; Mekkaden, M. V; Hall, D. S; Henry, G. W (Kluwer Academic Publishers, 1985-10)
    B andV photometry of DM UMa obtained between January, 1980 and June, 1984 is presented. Analysis yields a mean photometric period 7d.478±0d.010, compared to the known oribital period of 7d.492±0d.009. Light curves obtained ...
  • Extinction measurements at Leh 
    Singh, J; Bhattacharyya, J. C; Raveendran, A. V; Mohin, S; Ashoka, B. N (Astronomical Society of India, 1988-03)
    Observations were started at Leh in 1984 with a view to finding the possibility of setting up an astronomical observatory for infrared observations. Results of extinction measurements in UBV bands obtained on 12 nights ...
  • Fading of light maximum and linear polarization variation in the carbon Mira R Leporis 
    Raveendran, A. V (Royal Astronomical Society, 2002-11)
    Polarimetry of R Lep obtained over the years 1991-2002 is presented. During this period the star underwent an episode of fading of the brightness at light maximum, after an interval of about 35 yr. An analysis of the data ...
  • HD 22403: a New Variable with Ca II H and K Emission 
    Raveendran, A. V; Mohin, S; Mekkaden, M. V (Konkoly Observatory, 1985-03-26)
  • HD 81410 - A new RS CVn binary 
    Raveendran, A. V; Mekkaden, M. V; Mohin, S (Royal Astronomical Society, 1982-05)
    B and V photometry of HD 81410 obtained on 34 nights between January 3 and March 14 of 1981 is presented. In both B and V, the amplitudes are found to be approximately 0.15 mag. It is also found that a 12.86833 day period ...
  • Il Hydrae: new orbital solutions and bv photometry 
    Raveendran, A. V; Mekkaden, M. V (Konkoly Observatory, 1998-11)
    We present new orbital solutions of the primary of IL Hya combining all the available radial velocity measurements. We also present BV photometry obtained on 9 nights during January--March 1993.
  • An investigation of polarization produced by circumstellar dust envelopes 
    Raveendran, A. V (European Southern Observatory, 1991-03)
    Numerical computations show that: (1) the polarimetric behavior of carbon stars is inconsistent with the scattering by graphite grains, (2) the radial pulsation of the star does not significantly change the net polarization ...
  • The light variability of BD+25°2511 
    Raveendran, A. V (D. Reidel Publishing Company, 1984-02)
    Photometry of the spectroscopic binary BD +25°2511 obtained during the 1981, 1982, and 1983 observing seasons shows that it is a variable with a period of about 3.5 days.
  • Linear polarization in the RV Tauri star AR Puppis 
    Raveendran, A. V (Royal Astronomical Society, 1999-03)
    The UBVR polarimetry of AR Pup obtained on 14 nights during 1990-93 shows a large variation in both the amount (~ 6 per cent in the U band) and the wavelength dependence of polarization. The simultaneous photometry (20 ...
  • Long-term photometric variations of the active RS CVn binaries DM UMa and II Peg 
    Mohin, S; Raveendran, A. V; Mekkaden, M. V (International Astronomical Union, 1995)
  • Long-term polarimetric behaviour of the carbon Mira R Leporis 
    Raveendran, A. V; Kameswara Rao, N (European Southern Observatory, 1989-05)
    BVRI polarimetry of R Lep obtained during 1984-1987 shows large changes in the normalized wavelength dependence of polarization. It is found that both the amount and position angle of polarization had components which ...
  • Near simultaneous BV photometry and Hα spectroscopy of the RS Canum Venaticorum binary DM Ursae Majoris 
    Mohin, S; Raveendran, A. V (European Southern Obseravatory, 1994-06)
    Differential BV photometry of DM UMa obtained over 19 nights and near simultaneous Hα spectroscopy obtained over 7 nights during the 1990-91 observing season are presented. From an analysis of the available data we find ...
  • A new three-band, two beam astronomical photo-polarimeter 
    Srinivasulu, G; Raveendran, A. V; Muneer, S; Mekkaden, M. V; Jayavel, N; Somashekar, M. R; Sagayanathan, K; Ramamoorthy, S; Rosario, M.; Jayakumar, K (Astronomical Society of India, 2014-09)
    We designed and built a new astronomical photo-polarimeter that can measure linear polarization simultaneously in three spectral bands. It has a Calcite beamdisplacement prism as the analyzer. The ordinary and extra-ordinary ...
  • Observations of variables 
    Rosario, M. J; Muneer, S; Raveendran, A. V; Mekkaden, M. V (IBVS / Konkoly Observatory, 2010-12)
    UX Ari was observed on a total of 33 nights during December 2008-February 2010 in standard Johnson BV bands with the 34-cm tel escope of Vainu Bappu Observatory, Kavalur. All the measurements were made with respect to 62 ...
  • Observations of X-Per in optical domain 
    Sharma, D. P; Nagaraja, B. V; Bhattacharyya, J. C; Mohin, S; Raveendran, A. V (Kluwer Academic Publishers, 1983-09)
    We have monitored the X-ray source X-Per (4U 0352+30) on 31 August, 1979 through aU filter for about 1.5 hr using 102-cm telescope of Kavalur observatory. During this period intensity of X-Per fluctuated for some time, on ...
  • On the correlation between polarization and brightness in the RV Tauri Star AR Puppis 
    Raveendran, A. V (Kluwer Academic Publishers, 1999)

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