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Browsing by Author "Singh, J"

Browsing by Author "Singh, J"

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  • Singh, J; Sakurai, T; Ichimoto, K; Hiei, E (Astronomical Society of India, 2000)
    We have analysed the soft X-ray images of the sun obtained with the YOHKOH satellite, white light coronal images observed at Mauna Loa and H-alpha pictures of the sun taken at Mitaka and Kodaikanal to study helmet streamers. ...
  • Paniveni, U; Krishan, V; Singh, J; Srikanth, R (Springer, 2005-10)
    We employ fractal analysis to study the complexity of supergranulation structure using the Solar and Heliospheric Observatory (SOHO) dopplergrams. Our data consists of 200 visually selected supergranular cells, for which ...
  • Nagaraju, K; Sankarasubramanian, K; Rangarajan, K. E; Ramesh, K. B; Singh, J; Devendran, P; Hariharan (Astronomical Society of India, 2008-09)
    Calibration and characterization of a dual-beam polarimeter installed at Kodaikanal Tower Telescope (KTT) for spectropolarimetric observations are presented in this paper. It was found that a slit width of 48 μ is optimum ...
  • Raj Kumar, Nalla; Prasad, B. R; Singh, J; Venkata Suresh, Narra (Springer, 2018-04)
    The ground based observations of the coronal emission lines using a coronagraph are affected by the short duration of clear sky and varying sky transparency. These conditions do not permit to study small amplitude variations ...
  • Singh, J; Ravindra, B (Astronomical Society of India, 2011)
    The Indian Institute of Astrophysics has been making optical observations of the sun for more than a century by taking images of the sun in continuum to study the photosphere, Ca-K line and H-alpha line in order to study ...
  • Krishna Prasad, S; Banerjee, D; Singh, J (Springer, 2012-11)
    Active region fan loops in AR 11076 were studied, in search of oscillations, using high cadence spectroscopic observations from Extreme-ultraviolet Imaging Spectrometer (EIS) on board Hinode combined with imaging sequences ...
  • Priyal, Muthu; Singh, J; Ravindra, B; Chandar Shekar, B (Springer, 2019-09)
    We have digitized the Ca K images obtained at Kodaikanal Observatory with a pixel resolution of 0.86 arcsec and 16-bit readout to achieve better spatial and photometric accuracy. In addition to the general photometric ...
  • Ramani, M; Cowsik, R; Singh, J; Shukla, A. K (Wg. Cdr.); Ravi Shekar (Sqn. Ldr.); Narayana, P. V. S (Fg. Offr); Shaji, P. K (Fg. Offr.); Paul, S. K (Fg. Offr.); Shelkey, S. N (J.W.O); Babu, K. R (J.W.O); Kamble, V. B (Indian Institute of Astrophysics, Bangalore, 1997)
    The teams of the Indian Air Force participated actively in the programme. They made several supersonic flights to follow shadow zone of the moon on earth along the path of totality, thereby extending thte duration of ...
  • Raju, K. P; Sakurai, T; Ichimoto, K; Singh, J (The American Astronomical Society, 2000-11)
    The distribution of emission-line intensities, Doppler velocities, and line widths in a polar coronal hole and nearby regions are obtained from the spectroscopic observations carried out on 1998 November 3 at the Norikura ...
  • Priyal, M; Banerjee, D; Karak, B. B; Munoz-Jaramillo, A; Ravindra, B; Choudhuri, A. R; Singh, J (IOP Publishing, 2014-09-20)
    The Sun has a polar magnetic field which oscillates with the 11 yr sunspot cycle. This polar magnetic field is an important component of the dynamo process which operates in the solar convection zone and produces the sunspot ...
  • Raju, K. P; Singh, J; Srikanth, R; Chou, Dean-Yi; CA, TON team (Springer, 2001-03)
    We have obtained the temporal correlation function, Q(t), from time sequences of Caii K filtergrams and Dopplergrams from Antarctica, Taiwan Oscillation Network (TON) and Solar and Heliospheric Observatory (SOHO). Q(t) ...
  • Singh, J (Indian Academy of Sciences, 2008-06)
    Sun’s atmosphere is an ideal place to study and test many magnetohydrodynamic (MHD) processes controlling turbulent plasma. We wish to resolve some of the finest solar features (which remain unresolved presently) and study ...
  • Singh, J; Prasad, B. R; Venkatakrishnan, P; Sankarasubramanian, K; Banerjee, D; Bayanna, R; Mathew, S; Murthy, J; Subramaniam, P; Ramesh, R; Kathiravan, S; Nagabhushana, S; Mahesh, P. K; Manoharan, P. K; Uddin, W; Sriram, S; Amit Kumar; Srivastava, N; Koteswara Rao; Nagendra, C. L; Chakraborty, P; Sriram, K. V; Venkateswaran, R; Krishnamurthy, T; Sreekumar, P; Sarma, K. S; Murthy, R; Navalgund, K. H; Samudraiah, D. R. M; Narayan Babu, P; Patra, A (Indian Academy of Sciences, 2011-01-25)
    The outer atmosphere of the sun – called the corona – has been observed during total solar eclipse for short periods (typically < 6 min), from as early as the eighteenth century. In the recent past, space-based instruments ...
  • Paniveni, U; Krishan, V; Singh, J; Srikanth, R (Royal Astronomical Society, 2004-02-01)
    A study of 50 supergranular cells obtained from Solar and Heliospheric Observatory (SOHO) Dopplergrams was undertaken in order to investigate the relationship between the lifetime (T) and the horizontal flow velocity (vh) ...
  • Krishan, V; Paniveni, U; Singh, J; Srikanth, R (Royal Astronomical Society, 2002-07)
    A study of 90 supergranular cells obtained from SOHO Dopplergrams was undertaken in order to investigate a possible relation between the sizes and peak horizontal velocities of the cells. For the sample obtained, the two ...
  • Singh, J (Astronomical Society of India, 1998)
    We, at the Institute of Astrophysics, conducted ten experiments from two places namely Neem Ka Thana in Rajasthan and Kalpi in Uttar Pradesh. The experiments involved high spatial and spectral resolution spectroscopy to ...
  • Gupta, S. S; Singh, J (Astronomical Society of India, 1998)
    We have analysed the old data of calcium K line solar prominences obtained at Kodaikanal. The analysis indicated that the height of the quiescent prominence on the limb increases with its lifetime. In one case of prominence ...
  • Venkata Suresh, Narra; Prasad, B. R; Raj Kumar, Nalla; Singh, J (SPIE-The International Society for Optical Engineering, 2017-01)
    Visible emission line coronagraph (VELC) on board ADITYA-L1 mission is an internally occulted mirror coronagraph designed for solar coronal observations over a field of view (FOV) of 1.05 Ro to 3 Ro. To achieve the proposed ...
  • Cowsik, R; Singh, J; Raju, K. P; Saxena, A. K; Samson, J. P. A; Naidu, B. N (Indian Institute of Astrophysics, Bangalore, 1997)
    Narrow pass band hydrogen alpha filtergrams were obtained during totality at Kalpi, to look for cool pockets of H-alpha emission in corona first observed by Bappu and Bhattacharyya during the 1970 Mexican eclipse observations. ...
  • Cowsik, R; Singh, J; Saxena, A. K; Srinivasan, R; Raveendran, A. V (Kluwer Academic Publishers, 1999-08)
    Encouraged by the detection of high-frequency, low-amplitude continuum intensity oscillations in the solar corona during the total solar eclipse of 1995, we designed and fabricated a six-channel photometer incorporating ...

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