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  • Peculiarities in the Horizontal Branch Stars of Globular Cluster NGC 1851: Discovery of a Blue Straggler Companion to an EHB Star 
    Singh, G; Sahu, S; Subramaniam, A; Yadav, R. K. S (IOP Publishing, 2020-12-10)
    We present a study of far-UV (FUV) bright horizontal branch (HB) stars to understand the peculiarities seen in the HB sequence of the globular cluster NGC 1851, using ground- and space-based multiwavelength data. Optical ...
  • Peculiarities in the ionic tail of Comet Ikeya-Seki (1965f) 
    Krishan, V; Sivaraman, K. R (D. Reidel Publishing Co., 1982-04)
    Direct photographs of Comet Ikeya-Seki obtained on four consecutive days from October 29 to November 1, 1965, are used for an analysis of the multiple helical structures in the ionised tail. The formation of these structures ...
  • The pencil code, a modular MPI code for partial differential equations and particles: multipurpose and multiuser-maintained 
    The Pencil Code Collaboration; Brandenburg, Axel; Johansen, Anders; Bourdin, Philippe A; Dobler, Wolfgang; Lyra, Wladimi; Rheinhardt, Matthias; Bingert, Sven; Haugen, Nils Erland L; Mee, Antony; Gent, Frederick; Babkovskaia, Natalia; Yang, Chao-Chin; Heinemann, Tobias; Dintrans, Boris; Mitra, Dhrubaditya; Candelares, Simon; Warnecke, Jörn; Käpylä, Petri J; Li, Xiang-Yu; Krüger, Jonas; Aarnes, Jørgen R; Sarson, Graeme R; Oishi, Jeffrey S; Schober, Jennifer; Schreiber, Andreas; Chatterjee, Piyali; Käpylä, Maarit J; Plasson, Raphaël; Sandin, Christer; Karchniwy, Ewa; Rodrigues, Luiz Felippe S; Hubbard, Alexander; Guerrero, Gustavo; Snodin, Andrew; Losada, Illa R; Pekkilä, Johannes; Qian, Chengeng (2021-02-21)
    The Pencil Code is a highly modular physics-oriented simulation code that can be adapted to a wide range of applications. It is primarily designed to solve partial differential equations (PDEs) of compressible hydrodynamics ...
  • Penetration electric fields at the nightside dip equator associated with the main impulse of the storm sudden commencement of 8 July 1991 
    Sastri, J. H (American Geophysical Union, 2002-12)
    The geomagnetic storm sudden commencement (ssc) of 8 July 1991 was reported [Wilson et al., 2001] to be characterized by a reduction (enhancement) of X component at midlatitudes in the noon (midnight) sector in the 1-hour ...
  • Penetration of polar electric fields to the nightside dip equator at times of geomagnetic sudden commencements 
    Sastri, J. H; Rao, J. V. S. V; Ramesh, K. B (American Geophysical Union, 1993-10-01)
    Measurements of Doppler Velocity, V D of F - region reflections at normal incidence over Kodaikanal (dip 3°N, 77° 28′E) are used to study the nature of perturbations in F - region vertical plasma drift, V z associated with ...
  • Performance analysis of fourier and vector matrix multiply methods for phase reconstruction from slope measurements 
    Roopashree, M. B; Vyas, A; Prasad, B. R (Central Scientific Instruments Organisation (CSIR), 2009-11)
    The accuracy of wavefront reconstruction from discrete slope measurements depends on the sampling geometry, coherence length of the incoming wavefronts, wavefront sensor specifications and the accuracy of the reconstruction ...
  • Performance analysis of free space optical communication in open-atmospheric turbulence conditions with beam wandering compensation control 
    Anthonisamy, Arockia Bazil Raj; Durairaj, Padmavathi; Lancelot, J. P (IET, 2016-06-16)
    Among various atmospheric effects, beam wandering is the main cause for the major power loss in free space optical communication (FSOC) which cannot be resolved without incorporating the beam wandering compensation (BWC) ...
  • Performance Evaluation of Adaptive Optics Systems 
    Sridharan, R; Raja Bayanna, A; Srivastava, N; Kumar, B; Ravindra, B; Gupta, S. K; Jain, N; Ambastha, A; Venkatakrishnan, P (Astronomical Society of India, 2003)
    Adaptive Optics (AO) systems improve the resolution of ground based telescopes and allow for long exposure images. Their performance depends on the seeing conditions at the time of observations. In this paper, we evaluate ...
  • Performance evaluation of high-speed camera system for adaptive optics 
    Chinnappan, V; Saxena, A. K; Sreenivasan, A (Astronomical Society of India, 2002-09)
    Atmospheric turbulence distorts the incoming wavefront from the star light, thus severely limiting the resolution of the groundbased optical telescopes (Fried 1966). Adaptive optics is being implemented in all big ...
  • Performance of 10.5μm quantum well infrared photodetector for astronomical applications 
    Joseph, Celine; Saxena, A. K (Department of Applied Optics and Photonics, University of Calcutta, 2011)
  • Performance of a speckle interferometer 
    Saha, S. K; Jayarajan, A. P; Sudheendra, G; Chandra, A. U (Astronomical Society of India, 1997)
    An interferometer system for use at the 2.34 meter Vainu Bappu Telescope (VBT), situated at Vainu Bappu Observatory (VBO), Kavalur, to obtain speckle-grams of astronomical objects in the visible wavelength, has been ...
  • Performance of centroiding algorithms at low light level conditions in adaptive optics 
    Vyas, A; Roopashree, M. B; Prasad, B. R (The Institute of Electrical and Electronics Engineers, Inc, 2009)
    The performance metrics of different centroiding algorithms at low light level conditions were optimized in the case of a Shack Hartmann Sensor (SHS) for efficient performance of the adaptive optics system. For short ...
  • Performance of the IIA mosaic CCD camera system 
    Naidu, B. N; Srinivasan, R; Mohan, V; Sagar, R (Astronomical Society of India, 2001)
    We evaluate performance of the 4K x 4K mosaic CCD camera system developed at the Indian Institute of Astrophysics using four Thomson CCDs in a buttable configuration. The camera system consists of a mosaic CCD dewar developed ...
  • Performance of the low light level CCD camera for speckle imagmg 
    Saha, S. K; Chinnappan, V (Astronomical Society of India, 2002-09)
    A new generation CCD detector caJ.led low light level OOD (L3CCD) that performs like an intensified CCD without incorporating a micro channel plate (MOP) for light amplification was procured and tested. A series of ...
  • Performance of the UVIT Level-2 pipeline 
    Ghosh, S. K; Tandon, S. N; Joseph, P; Devaraj, A; Shelat, D. S; Stalin, C. S (Indian Academy of Sciences, 2021-10)
    Performance of the Level-2 pipeline, which translates the UVIT data created by the ISRO’s ground segment processing systems (Level-1) into astronomer ready scientific data products, is described. This pipeline has evolved ...
  • Performance results of HESP physical model 
    Anantha, Ch; Sivarani, T; Jones, D; Giridhar, S; Grobler, D; Jakobsson, R (2017-02)
    As a continuation to the published work on model based calibration technique with HESP(Hanle Echelle Spectrograph) as a case study, in this paper we present the performance results of the technique. We also describe how ...
  • Performance studies of the PACT experiment 
    Vishwanath, P. R; Acharya, B. S; Bhat, P. N; Chitnis, V. R; Majumdar, P; Rahman, M. A; Singh, B. B (Astronomical Society of India, 2002)
    Monte Carlo calculations have been done to understand various characteristics like the energy threshold, collection area etc of the recently commissioned PACT. The energy threshold of the array for gamma rays is found to ...
  • Period changes in the RR Lyrae stars of NGC 6171 (M107) 
    Arellano Ferro, A; Rosenzweig, P; Luna, A; Deras, D; Muneer, S; Giridhar, S; Michel, R (WILEY-VCH Verlag GmbH & Co., 2018-02)
    Based on photometric data obtained between 1935 and 2017, O −C diagrams were built for 22 RR Lyrae stars in the globular cluster NGC 6171, leading to the discovery of secular period changes in four variables for which we ...
  • Period study of the Algol-type eclipsing binary - R Canis Majoris 
    Radhakrishnan, K. R; Abhyankar, K. D; Sarma, M. B. K (Astronomical Society of India, 1984-06)
    Photoelectric observations of the Algol-type eclipsing binary R Canis Majoris during three consequtive observing seasons of 1979-82 gave a total of ten primary minima in each of the V and B passbands and nine in the U ...
  • Period study of the RS CVn eclipsing binary SV Camelopardalis 
    Sarma, C. V. S. R; Sarma, M. B. K; Abhyankar, K. D (Astronomical Society of India, 1985-12)
    Using the available photographic and photoelectric times of minima, we have revised the elements of the light-time orbit of SV Camelopaedalis, an RS CVn type eclpsing binary. Taking a mass function of 0.118 M and the ...

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