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Browsing by Author "Parihar, P. S"

Browsing by Author "Parihar, P. S"

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  • Design and development of a mirror support system for prototype segmented mirror telescope 
    Govinda, K. V; Parihar, P. S; Kemkar, P. M. M; Goudar, Abhishek; Sandeep, D. S; Muthahar, R. Mohammed; Sagayanathan, K; Dharmadhikari, Radhika; Divya, P. H (SPIE-The International Society for Optical Engineering, 2022-08)
    The segment support system of any segmented mirror telescope is considered to be one of the most critical subsystem. The segment support not only holds the mirror without altering its figure, but also features mechanism ...
  • Design, development, and validation of a segment support actuator for the prototype segmented mirror telescope 
    Deshmukh, P. G; Mandal, A; Parihar, P. S; Nayak, D; Mishra, Deepta Sundar (SPIE-The International Society for Optical Engineering, 2018-01)
    Segmented mirror telescopes (SMT) are built using several small hexagonal mirrors positioned and aligned by the three actuators and six edge sensors per segment to maintain the shape of the primary mirror. The actuators ...
  • Development of a Lunar Scintillometer as part of the national large optical telescope site survey 
    Surendran, A; Parihar, P. S; Banyal, R. K; Anusha Kalyaan (Springer, 2018-03)
    Ground layer turbulence is a very important site characterization parameter used to assess the quality of an astronomical site. The Lunar Scintillometer is a simple and effective site-testing device for measuring the ...
  • Dynamic Loading Assembly for Testing Actuators of Segmented Mirror Telescope 
    Prasanna Deshmukh; Parihar, P. S; Balasubramaniam, K. A; Mishra, Deepta Sundar; Mahesh, P. K (World Scientific Publishing Co., 2017-09)
    Upcoming large telescopes are based on Segmented Mirror Telescope (SMT) technology which uses small hexagonal mirror segments placed side by side to form the large monolithic surface. The segments alignment needs to be ...
  • Exploring pre-main sequence variables of ONC: the new variables 
    Parihar, P. S; Messina, S; Distefano, E; Shantikumar, N. S; Medhi, B. J (Wiley Blackwell, 2009-07)
    Since 2004, we have been engaged in a long-term observing program to monitor young stellar objects in the Orion Nebula Cluster. We have collected about two thousands frames in V, R, and I broad-band filters on more than ...
  • FR Cnc revisited: photometry, polarimetry and spectroscopy 
    Golovin, A; Galvez-Ortiz, M. C; Hernan-Obispo, M; Andreev, M; Barnes, J. R; Montes, D; Pavlenko, E; Pandey, J. C; Martinez-Arnaiz, R; Medhi, B. J; Parihar, P. S; Henden, A; Sergeev, A; Zaitsev, S. V; Karpov, N (Wiley-Blackwell, 2012-03)
    This paper is part of a multiwavelength study aimed at using complementary photometric, polarimetric and spectroscopic data to achieve an understanding of the activity process in late-type stars. Here, we present the ...
  • Impact of photometric variability on age and mass determination in young stellar objects: the case of the Orion Nebula Cluster 
    Messina, S; Parihar, P. S; Distefano, E (IOP Publishing, 2017-06)
    Very young stars, like the Orion Nebula Cluster (ONC) members analysed in the present study, exhibit photometric variability with a wide range of amplitudes. Such a prominent variability reflects in the inferred values of ...
  • An improved Technique to Explore Disk Accretion Process in PMS Stars 
    Parihar, P. S (Springer, 2010)
    The low mass PMS stars are found to be surrounded by thick, flared accretion disk and the disk material is supposed to be funneled onto the stellar surface by strong and predominately dipolar magnetic field. We have developed ...
  • Magnetic activity in the photosphere of CoRoT-Exo-2a. Active longitudes and short-term spot cycle in a young Sun-like star 
    Lanza, A. F; Pagano, I; Leto, G; Messina, S; Aigrain, S; Alonso, R; Auvergne, M; Baglin, A; Barge, P; Bonomo, A. S; Boumier, P; Collier Cameron, A; Comparato, M; Cutispoto, G; de Medeiros, J. R; Foing, B; Kaiser, A; Moutou, C; Parihar, P. S; Silva-Valio, A; Weiss, W. W (EDP Sciences, 2009-01)
    Context: The space experiment CoRoT has recently detected transits by a hot Jupiter across the disc of an active G7V star (CoRoT-Exo-2a) that can be considered as a good proxy for the Sun at an age of approximately 0.5 ...
  • Night sky at the Indian Astronomical Observatory during 2000-2008 
    Stalin, C. S; Hegde, M; Sahu, D. K; Parihar, P. S; Anupama, G. C; Bhatt, B. C; Prabhu, T. P (Astronomical Society of India, 2008-09)
    This paper presents an analysis of the optical night sky brightness and extinction coefficient measurements in UBVRI at the Indian Astronomical Observatory (IAO), Hanle, during the period 2000–2008. They are obtained from ...
  • Night Sky Extinction Measurements at the Indian Astronomical Observatory, Hanle 
    Parihar, P. S; Sahu, D. K; Bhatt, B. C; Subramaniam, A; Anupama, G. C; Prabhu, T. P (Astronomical Society of India, 2003)
    We present the estimates of the night sky extinction at the Indian Astronomical Observatory. Also presented are the estimates of the night sky brightness. The extinction in the U band at IAO is found to be lower than the ...
  • Observation of R-Band Variability of L Dwarfs 
    Maiti, M; Sengupta, S; Parihar, P. S; Anupama, G. C (University of Chicago Press, 2005-02)
    We report, for the first time, photometric variability of L dwarfs in the R band. Out of three L1 dwarfs (2MASS 1300+19, 2MASS 1439+19, and 2MASS 1658+70) observed, we have detected R-band variability in 2MASS 1300+19 and ...
  • The optical afterglow of the not so dark GRB 021211 
    Pandey, S. B; Anupama, G. C; Sagar, R; Bhattacharya, D; Castro-Tirado, A. J; Sahu, D. K; Parihar, P. S; Prabhu, T. P (The European Southern Observatory, 2003-09)
    We determine Johnson B,V and Cousins R,I photometric CCD magnitudes for the afterglow of GRB 021211 during the first night after the GRB trigger. The afterglow was very faint and would have been probably missed if no prompt ...
  • Optical observations of the bright long duration peculiar GRB 021004 afterglow. 
    Pandey, S. B; Sahu, D. K; Resmi, L; Sagar, R; Anupama, G. C; Bhattacharya, D; Mohan, V; Prabhu, T. P; Bhatt, B. C; Pandey, J. C; Parihar, P. S; Castro-Tirado, A. J (Astronomical Society of India, 2003)
    The CCD magnitudes in Johnson B,V and Cousins R and I photometric passbands are determined for the bright long duration GRB 021004 afterglow from 2002 October 4 to 16 starting ~ 3 hours after the γ - ray burst. Light curves ...
  • Photometry and spectroscopy of II Peg, IM Peg and UX Ari 
    Dar, A. A; Parihar, P. S; Malik, M. A (IOP Publishing, 2018-08)
    V band photometry of three RS CVn stars, II Peg, IM Peg and UX Ari, is carried out to study the physical properties of these variables. We verified the significant and regular optical photometric variability to be present ...
  • Physical parameters and long-term photometric variability of V1481 Ori, an SB2 member of Orion nebula Cluster with an accreting component 
    Messina, S; Parihar, P. S; Biazzo, K; Lanza, A. F; Distefano, E; Melo, C. H. F; Bradstreet, D. H; Herbst, W (Oxford University Press on behalf of the Royal Astronomical Society, 2016-04)
    We present the results of our analysis on V1481 Ori (JW 239), a young SB2 in the Orion nebula Cluster with a circumbinary disc accreting on the lower mass component. The analysis is based on high-resolution spectroscopic ...
  • Post-outburst phase of McNeil's nebula (V1647 Orionis) 
    Ojha, D. K; Ghosh, S. K; Tej, A; Verma, R. P; Vig, S; Anupama, G. C; Sahu, D. K; Parihar, P. S; Bhatt, B. C; Prabhu, T. P; Maheswar, G; Bhatt, H. C; Anandarao, B. G; Venkataraman, V (Blackwell Publishing, 2006-03)
    We present a detailed study of the post-outburst phase of McNeil's nebula (V1647 Orionis) using optical B, V, R, I and near-infrared (NIR) J, H, K photometric and low-resolution optical spectroscopic observations. The ...
  • Precision controller for segmented mirror telescope actuator: control and tuning 
    Prasanna Deshmukh; Parihar, P. S (IEEE, 2016-03)
    The segmented mirror telescopes are built using small hexagonal mirrors positioned and aligned by the three actuators and six edge sensors per segment to maintain the shape of the primary mirror. The global loop controller ...
  • Primary Mirror Active Control System Simulation of Prototype Segmented Mirror Telescope 
    Prasanna Deshmukh; Mishra, Deepta Sundar; Parihar, P. S; Vedashree (IEEE, 2017-01)
    The upcoming large astronomical telescopes are trending towards the Segmented Mirror Telescope (SMT) technology, initially developed at the W M Keck Observatory in Hawaii, where two largest SMTs in the world are in use. ...
  • The RACE-OC project: Rotation and ACtivity Evolution in Open Clusters 
    Messina, S; Distefano, E; Parihar, P. S; Busa, I; Cutispoto, G; Lanza, A.F; Lanzafame, A; Pagano, I; Biazzo, K; Leto, G; Hatzidimitriou, D; Kim, S. -L; Koo, J. -R; Kang, Y. B (American Institute of Physics, 2009)
    The RACE‐OC project, standing for Rotation and Activity Evolution in Open Clusters, is a long‐term project aimed at studying the evolution of rotation and magnetic activity of late‐type members of stellar open clusters. ...

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