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Browsing by Author "Ashoka, B. N"

Browsing by Author "Ashoka, B. N"

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  • Detection of optical pulsations from RX J0558.0+5353 
    Ashoka, B. N; Marar, T. M. K; Seetha, S; Kasturirangan, K; Bhattacharyya, J. C (The European Southern Observatory, 1995-05)
    We report the detection of optical pulsations at a period of 272.785+-0.003s from the newly discovered intermediate polar RX J0558.0+5353. This period nearly coincides with the X-ray period reported by Haberl et al. (1994). ...
  • Discovery of pulsations in HD 98851 
    Joshi, S; Girish, V; Martinez, P; Sagar, R; Ashoka, B. N; Gupta, S. K; Seetha, S; Chaubey, U. S; Kurtz, D. W (Astronomical Society of India, 2001)
    Using the UPSO 1-m Sampurnanand reflector telescope equipped with a fast photometer, we observed the chemically peculiar (CP) star HD 98851 for a total of around 30 hours on 5 different nights between January to April 2000. ...
  • The eccentric double-lined binary BD - 1 deg 1004 
    Kameswara Rao, N; Ashoka, B. N; Lloyd, C; Pike, C. D; Stickland, D. J (Indian Academy of Sciences, 1990-12)
    A new radial velocity study has been made of the highly eccentric, early-type binary BD - 1 deg 1004 using spectra from the Kavalur Observatory. All available archival material has also been reexamined. An attempt has been ...
  • Evolution of the optical spectrum of SN 1987a in the Large Magellanic Cloud 
    Ashoka, B. N; Anupama, G. C; Prabhu, T. P; Giridhar, S; Ghosh, K. K; Jain, S. K; Pati, A. K; Kameswara Rao, N (Indian Academy of Sciences, 1987-06)
    The evolution of the spectrum of SN 1987a is traced from 1987 February 26 to March 31. Based on the low-resolution spectroscopic data the authors identify the lines of H, He I, Na I, Fe II, Sc II, Ca II which are known to ...
  • 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 ...
  • Further photometric observations of the cataclysmic variable PG 1012-029 
    Ashoka, B. N; Marar, T. M. K; Seetha, S; Kasturirangan, K; Rao, U. R; Bhattacharyya, J. C (Kluwer Academic Publishers, 1993)
    We report time series photometric observations of PG 1012-029, conducted during 1990 and 1991. Light curves of three consecutive eclipses recorded in a single night are presented. The enhanced pre-eclipse hump in our data ...
  • Further spectroscopic observations of SN 1987A 
    Anupama, G. C; Prabhu, T. P; Ghosh, K. K; Ashoka, B. N; Giridhar, S (Elsevier, 1988)
    Spectroscopic observations of SN 1987a obtained during 1987 August 30 – September 8 from Vainu Bappu Observatory, Kavalur, are presented; the spectrum is compared and contrasted with the spectra recorded at earlier epochs. ...
  • HD 12098 a new far-northern roAp star 
    Girish, V; Joshi, S; Seetha, S; Ashoka, B. N; Martinez, P; Chaubey, U. S; Gupta, S. K; Kurtz, D. W; Sagar, R (Astronomical Society of India, 2001)
    The rapidly oscillating Ap (roAp) stars are cool, magnetic, chemically peculiar stars which pulsate in non-radial p-modes in the period range 4-16 min and have Johnson B amplitudes less than 8 mmag. "The NainiTal-Cape ...
  • High speed photometry of PG 1012-029 
    Ashoka, B. N; Seetha, S; Marar, T. M. K; Kasturirangan, K; Rao, U. R; Bhattacharyya, J. C (European Southern Observatory, 1994-03)
    High speed optical photometric observations of PG 1012 - 029, conducted during 1990-1991, confirm the nova-like classification of the object. Several eclipses observed by us have been used to refine the orbital period of ...
  • The Intermediate Polar PQ GEM -- Status of Wet Observations of 1996 
    Marar, T. M. K; Seetha, S; Ashoka, B. N; Kasturirangan, K; Mahra, H. S; Bhattacharyya, J. C; Leibowitz, E. M; Hemar, S; Mendelson, H; Ibbetson, P. A; O'Donoghue, D; Buckley, D. A. H; Breger, M; Handler, G; Sperl, M; Serkowitsch, E; Moskalik, P; Zola, S; Pajdosz, G; Krzesinski, J; Silvotti, R; Vauclair, G; Dolez, N; Solheim, J. E; Pfeiffer, B; Kepler, S. O; Kanaan, A; Provencal, J; Kawaler, S. D; O'Brien, M. S; Nather, R. E; Winget, D. E; Kleinman, S; Nitta, A; Bradley, P. A; Guzik, J. A; Clemens, C; Sullivan, D. J; Jiang, X (Baltic Astronomy, 1998-03)
    A summary of the results on PQ Gem based on WET observations conducted in February 1996 is presented. The 13.9 min spin period of the white dwarf in the system and the orbital side-band at 14.5 min have been detected ...
  • Naini Tal-Cape survey for pulsating chemically peculiar stars - A status report 
    Seetha, S; Chaubey, U. S; Girish, V; Joshi, S; Ashoka, B. N; Gupta, S. K; Kurtz, D. W; Martinez, P; Sagar, R (Astronomical Society of India, 2001)
    The "Naini Tal-Cape survey for rapidly oscillating Ap stars", to search the northern hemi-sphere sky for pulsating stars was initiated in 1997. This is a collaboration between India and South Africa. So far about 70 stars ...
  • New pulsating variables discovered from the Naini Tal-Cape survey 
    Seetha, S; Ashoka, B. N; Joshi, S; Girish, V; Sagar, R; Chaubey, U. S; Gupta, S. K (Astronomical Society of India, 2002-09)
    The Naini Tal-Cape survey has been initiated to search for pulsations in chemically peculiar A and F type stars. Many of the magnetic A peculiar type stars exhibit rapid oscillations with periods ranging from 4-16 minutes. ...
  • 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 ...
  • Photoelectric Observations of R CrB during the Recent Light Minimum 
    Ashoka, B. N; Pukalenthi, S (Konkoly Observatory, 1986-06)
  • Photometric and radial velocity variations of RCrB near maximum light 
    Raveendran, A. V; Ashoka, B. N; Kameswara Rao, N (D. Reidel Publishing Co, 1986)
    Fourier analysis of the light curves of R CrB in the V band near maximum shows that in addition to several significant short periods there is a modulation of the visual light with a period around 1170 days, similar to that ...
  • Photometric observations of cataclysmic variables from UPSO, Naini Tal 
    Ashoka, B. N; Seetha, S; Marar, T. M. K; Raj, E; Kasturirangan, K; Mahra, H. S (Astronomical Society of India, 1998)
  • Photometric observations of the AM CVn star EC 15330-1403 
    Seetha, S; Ashoka, B. N; Raj, E; Kasturirangan, K (Astronomical Society of India, 2000)
  • Spectrophotometric observations of R CrB during 1972, 74 Minima 
    Kameswara Rao, N; Vasundhara, R; Ashoka, B. N (D. Reidel Publishing Co, 1986)
  • Spectroscopic observations of Nu Centauri 
    Ashoka, B. N; Surendiranath, R; Kameswara Rao, N (Copernicus Foundation for Polish Astronomy, 1985)
    Presented are radial-velocity observations of the single-line spectroscopic binary and Beta Cephei-type variable Nu Cen, obtained in the period 1983-1984. New orbital elements have been determined by combining these ...
  • Spectroscopic studies of R CrB during light minima - Absorption spectrum 
    Kameswara Rao, N; Giridhar, S; Ashoka, B. N (Royal Astronomical Society, 1990-05)
    R CrB was observed during the 1986 shallow minimum to study the spectral changes taking place during light minimum as compared with the spectrum at maximum light. The absorption spectrum at this minimum is very similar to ...

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