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Browsing by Author "Singh, J"

Browsing by Author "Singh, J"

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  • Photography of Solar Corona Using Indian Air Force Aeroplane 
    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 ...
  • The Physical Conditions in a Polar Coronal Hole and Nearby Regions from Norikura and SOHO Observations 
    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 ...
  • Polar Network Index as a Magnetic Proxy for the Solar Cycle Studies 
    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 ...
  • Possible Evidence of Long-Term Oscillations in the Solar Atmosphere 
    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) ...
  • Proposed National Large Solar Telescope 
    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 ...
  • Proposed visible emission line space solar coronagraph 
    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 ...
  • Relationship between horizontal flow velocity and cell lifetime for supergranulation from SOHO Dopplergrams 
    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) ...
  • Relationship between horizontal flow velocity and cell size for supergranulation using SOHO Dopplergrams 
    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 ...
  • Results of 1995 eclipse observation and observing program for 1998 and 1999 eclipses 
    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 ...
  • Role of field lines in the case of an eruptive prominence 
    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 ...
  • Scatter studies for visible emission line coronagraph on board ADITYA-L1 mission 
    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 ...
  • Search for Hydrogen-alpha Emitting Cool Pockets in Corona During the Total Solar Eclipse of October 24, 1995 
    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. ...
  • Short-period intensity oscillations in the solar corona observed during the total solar eclipse of 26 February 1998 
    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 ...
  • Solar coronal magnetic fields and sensitivity requirements for spectropolarimetry channel of VELC onboard Aditya-L1 
    Sasikumar Raja, K; Venkata Suresh, Narra; Singh, J; Prasad, B. R (Elsevier, 2022-01-01)
    Understanding solar coronal magnetic fields is crucial to address the long-standing mysteries of the solar corona and solar wind. Although routine photospheric magnetic fields (MFs) are available for decades, coronal MFs ...
  • Solar Cycle Phase Dependence of Supergranular Fractal Dimension 
    Paniveni, U; Krishan, V; Singh, J; Srikanth, R (Indian Academy of Sciences, 2011-06)
    We study the complexity of supergranular cells using the intensity patterns obtained from the Kodaikanal Solar Observatory during the 23rd solar cycle. Our data consists of visually identified supergranular cells, from ...
  • Solar Optical Observations from Kodaikanal and from Eclipses 
    Singh, J (Indian Institute of Astrophysics, Bangalore, 1986)
    From an analysis of a long series of Calcium K spectroheliograms taken at Kodaikanal, systematic changes in the sizes of supergranule cells have been found. The average cell size changes with the phase of solar cycle, being ...
  • Solid state coelostat drive system for a telescope 
    Srinivasan, R; Singh, J; Ramamoorthy, K. S (Indian Institute of Astrophysics, 1989-07)
  • 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 ...
  • 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 ...
  • Spatio-temporal fluctuations in He I 10830 A line parameters - Evidence for spicule formation 
    Venkatakrishnan, P; Jain, S. K; Singh, J; Recely, F; Livingston, W. C (Springer Netherlands, 1992-03)
    The equivalent width, line depth, line width, and Doppler shift of the He i 10830 Å line were extracted from two time series of spectra. Scatter plots of time-averaged line depth, line width, and Doppler shifts, as well ...

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