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Browsing by Author "Jain, S. K"

Browsing by Author "Jain, S. K"

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  • Analysis of Ca(+) K plage area for short period variation 
    Singh, J; Jain, S. K (Indian Academy of Sciences, 1989-12)
    Observations of solar Ca(+) K daily plage area from 1951 to 1977 are analyzed to search for short-period (12-13 day) variations. The 27-day periodicity due to solar rotation modulation is found at all latitudes. Using an ...
  • Design and test of a high-resolution EUV spectroheliometer 
    Berger, T. E; Timothy, J. G; Walker II, A. B. C; Kirby, H; Morgan, J. S; Jain, S. K; Saxena, A. K; Huber, M. H; Tondello, G; Naletto, G (SPIE-The International Society for Optical Engineering, 1992)
    The HiRES High-Resolution EUV Spectroheliometer is a sounding rocket instrument yielding very high spatial, spectral, and temporal resolution images of the solar outer atmosphere, on the basis of a 45-cm Gregorian telescope ...
  • Evidence of expansion in the central region of NGC 2346 
    Banerjee, D. P. K; Anandarao, B. G; Desai, J. N; Jain, S. K; Mallik, D. C. V (International Astronomical Union, 1989)
  • 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 ...
  • HiRES - A high-resolution stigmatic extreme ultraviolet spectroheliometer for studies of the fine-scale structure of the solar chromosphere, transition region, and corona 
    Timothy, J. G; Berger, T. E; Morgan, J. S; Walker, A. B. C; Jain, S. K; Saxena, A. K; Bhattacharyya, J. C; Huber, M. C. E; Tondello, G; Naletto, G (SPIE, 1991-08)
    HiRES is a high-resolution stigmatic EUV spectroheliometer whose 45-cm Gregory telescope is coupled to a spectrometer employing a single toroidal diffraction grating and an imaging pulse-counting multianode microchannel ...
  • HiRES: high resolution extreme ultraviolet spectroheliometer 
    Berger, T; Bergamini, P; Kirby, H; Timothy, J. G; Walker, A. B. C; Bhattacharyya, J. C; Jain, S. K; Saxena, A. K; Huber, M. C. E; Naletto, G; Tondello, G (Cambridge University Press, 1993)
    The HiRES sounding rocket payload is designed to obtain very high spatial, spectral, and temporal resolution images of the solar chromospheric and coronal plasmas in the extreme ultraviolet (EUV) wavelength range from 500 ...
  • HiRES: High-resolution extreme-ultraviolet spectroheliometer toroidal diffraction grating performance evaluation 
    Berger, T. E; Bergamini, P; Walker II, A. B. C; Jain, S. K; Saxena, A. K; Bhattacharyya, J. C; Huber, M. H; Tondello, G; Naletto, G; Baker, P. C (SPIE-The International Society for Optical Engineering, 1993)
    The HiRES sounding rocket payload has been described in detail in previous SPIE Proceedings. Here, optical design of the toroidal grating spectrograph is presented and discussed. Ray tracing results are presented which ...
  • Kinematic studies of five galactic planetary nebulae 
    Banerjee, D. P. K; Anandarao, B. G; Jain, S. K; Mallik, D. C. V (The European Southern Observatory, 1990-12)
    High-resolution Fabry-Perot observations have been made to determine the velocity structure of five PNe and to subsequently relate the observations to the morphology of the objects. New kinematic data on one of these PNe, ...
  • Measurements of linear polarization of some Herbig Ae/Be stars 
    Jain, S. K; Bhatt, H. C; Sagar, R (The American Physical Society, 1990-05)
    The linear polarization of eight bright Herbig Ae/Be stars in UBVRI bands has been measured. No unique wavelength dependence of polarization magnitude or direction is found in these measurements. Comparison with earlier ...
  • Morphology of the bipolar planetary nebula NGC 2346 from emission line profile studies 
    Anandarao, B. G; Banerjee, D. P. K; Desai, J. N; Jain, S. K; Mallik, D. C. V (Royal Astronomical Society, 1988-11)
    High resolution observations of H-alpha 6563-A, forbidden O-III 5007 A, and forbidden N-II 6583-A emission lines in the bipolar planetary nebula NGC 2346 are presented. From the widths of the alpha and forbidden N-II lines, ...
  • On the absorption of He I 10830 Å line by spicules 
    Venkatakrishnan, P; Jain, S. K (Astronomical Society of India, 1983)
    The possible applications of the time-dependent measurements of the equivalent width of the He I 10830 A line for a better understanding of the growth of spicules and the evolution of coronal holes and x-ray bright points ...
  • Polarization Maps for the Dark Clouds B:227 and L:121 
    Bhatt, H. C; Jain, S. K (European Southern Observatory, 1993-09)
    Optical linear polarization measurements for stars in the regions of the molecular clouds B 227 and L 121 are presented. The magnetic field geometry in the clouds as indicated by the polarization maps is discussed in ...
  • Polarization Measurements of Post-Asymptotic Giant Branch Candidates and Related Stars 
    Parthasarathy, M; Jain, S. K; Sarkar, G (The American Astronomical Society, 2005-05)
    We have obtained UBVRI polarization measurements of 26 post-asymptotic giant branch (post-AGB) candidates and related stars. The extremely metal-poor post-AGB star HR 4049 has been observed several times. In most cases we ...
  • Polarization Measurements of Some Herbig Ae / Be-Stars 
    Jain, S. K; Bhatt, H. C; Sagar, R (International Astronomical Union, 1990)
    We have measured the linear polarization of 8 bright Herbing Ae/ Be starsin UBVRI bands. No unique wavelength dependence of magnitude as well as direction is found on these measurements.
  • Polarization measurements of stars in the region of the nearby molecular cloud MBM 12 
    Bhatt, H. C; Jain, S. K (Blackwell Publishing, 1992-07)
    Linear polarization measurements of stars in the region of the nearby high-latitude molecular cloud MBM 12 are presented. Stars behind the cloud show a polarization of about 2-3 percent, while stars that are in front of ...
  • Polarization measurements of the luminous blue variable HR Carinae 
    Parthasarathy, M; Jain, S. K; Bhatt, H. C (European Southern Observatory, 2000-03)
    We have made BVRI polarization measurements of HR Car on ten occasions during the period JD 2447919 to JD 2449014. All our observations are on the rising part of the light curve. We find the presence of intrinsic variable ...
  • Possible young stellar objects in the region of the Cygnus OB2 (VI Cygni) association from IRAS observations 
    Parthasarathy, M; Jain, S. K; Bhatt, H. C (EDP Sciences, 1992-12)
    Several massive young stellar objects are found from an analysis of the 12- to 100-micron flux data of IRAS sources in the region of the Cyg OB2 association. Sixty-four sources with positive spectral indices and steeply ...
  • The Puppis OB III association: polarization measurements 
    Bhatt, H. C; Jain, S. K; Sagar, R (European Southern Observatory, 1998-03)
    Optical linear polarization measurements of association members and field stars in the region of the Puppis OB III association are presented. The association members are found to have larger values of polarization than the ...
  • A rapid scan Fourier transform infrared spectrometer 
    Jain, S. K; Smyth, M. J (Astronomical Society of Indian, 1988-12)
    A rapid scan Fourier transform spectrometer for astronomical infrared spectroscopy, tested at the Cassegrain focus of the 102 cm telescope at Kavalur, is described. The design of the fore-optics and the performance of the ...
  • Red and reddened stars in the region of Cygnus OB2 (VI Cygni) association 
    Parthasarathy, M; Jain, S. K (European Southern Observatory, 1995-06)
    From an ultra-low dispersion spectroscopic survey of the Cyg OB2 association several red and reddened stars are detected. Most of these stars appear to be reddened early-type stars belonging to the Cygnus OB2 association. ...

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