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  • Dramatic Changes in the Polarization of AR Pup 
    Raveendran, A. V; Deshpande, M. R; Kameswara Rao, N; Joshi, U. C; Kuleshrestha, A. K (Konkoly Observatory, 1985-04-25)
  • Drive control system for the TACTIC γ-ray telescope 
    Tickoo, A. K; Koul, R; Kaul, S. K; Kaul, I. K; Bhat, C. L; Bhatt, N (Astronomical Society of India, 1999)
    We present here some salient features of the hardware and software aspects of the 2-axes drive system developed for the TACTIC γ-ray telescope array. A test-report of its performance is also presented
  • A DSO-based system for temporal-profile extraction of atmospheric Cerenkov events 
    Tickoo, A. K; Kaul, S. K; Kaul, I. K; Koul, R; Bhat, C. L (Astronomical Society of India, 2000)
    The TACTIC array of Cerenkov telescopes, being set up at Mt. Abu, proposes to record time-profiles of atmospheric Cerenkov pulses with a view to exploit apparent differences in the associated time-parameters for a possible ...
  • Dual Active Galactic Nuclei in Nearby Galaxies 
    Mousumi Das; Rubinur, K; Preethi, K; Varghese, A; Novakkuni, N; James, A (Societe Royale des Sciences de Liege, 2018-04)
    Galaxy mergers play a crucial role in the formation of massive galaxies and the buildup of their bulges. An important aspect of the merging process is the in-spiral of the supermassive black-holes (SMBHs) to the centre ...
  • A dual cavity Fabry-Perot device for high precision doppler measurements in astronomy 
    Banyal, R. K; Reiners, A (World Scientific Publishing Co., 2017-03)
    We propose a dual cavity Fabry–Perot interferometer as a wavelength calibrator and a stability tracking device for astronomical spectrograph. The FPI consists of two adjoining cavities engraved on a low expansion monoblock ...
  • A Dual Fabry-Perot based imaging Spectrometer for the National Large Solar Telescope 
    Ravindra, B; Banyal, R. K (Indian Institute of Astrophysics, 2010)
    This report provides a detailed design of a dual Fabry-Perot based narrow band imaging system intended to make observations of solar atmosphere at visible and near infrared wavelengths. The narrow band imager will serve ...
  • A dual Fabry-Perot based narrow band imager for the National Large Solar Telescope 
    Ravindra, B; Banyal, R. K (Astronomical Society of India, 2011)
    A large solar telescope is usually equipped with several postfocus instruments deployed to study the dynamics of the solar features at di erent wavelengths. Indian Institute of Astrophysics (IIA) has proposed to build ...
  • Dual frequency observations of solar microwave bursts using the VLA 
    Shevgaonkar, R. K; Kundu, M. R (The American Astronomical Society, 1985-05)
    Simultaneous VLA observations of microwave bursts at 6 and 2 cm in a solar active region are presented and discussed. Using the full-day synthesis, I and V maps of the active region are produced. The radiation mechanisms ...
  • Dual input null networks utilizing RC ladders 
    Sen Roy, N (PID [Publications and Information Directorate], 1968)
    Two RC ladder networks are presented each of which, with an auxiliary input channel, shows transmission zero at a frequency that can be varied simply and widely by varying the ratio of the two inputs
  • Duration of equatorial spread-F 
    Sastri, J. H (Copernicus Publications, 1984-06)
    From an analysis of ionogram data of Kodaikanal (dip 3.5 deg N) for a 3-yr period of high sunspot activity, it is shown that the duration of equatorial spread-F (ESF), on the average, bears a direct relationship to the ...
  • Duration of Polar Activity Cycles and Their Relation to Sunspot Activity 
    Makarov, V. I; Tlatov, A. G; Sivaraman, K. R (Springer, 2003-05)
    We have defined the duration of polar magnetic activity as the time interval between two successive polar reversals. The epochs of the polarity reversals of the magnetic field at the poles of the Sun have been determined ...
  • Duration of star formation in young open clusters 
    Bhavya, B; Subramaniam, A; Kuriakose, V. C (Astronomical Society of India, 2012)
    Young Open Clusters have always been a platform for the star formation studies. It was assumed that all members in the cluster are coeval, on the other hand, recent studies show the presence of an age range among the members ...
  • Dust and ionized gas in NGC 3607 
    Singh, K. P; Prabhu, T. P; Kembhavi, A. K; Bhat, P. N (The American Astronomical Society, 1994-04)
    We report the detection of a broad dust ring in the X-ray-bright elliptical galaxy NGC 3607, the dominant member of a nearby group of galaxies. The inner radius of the ring is approximately 1.3 kpc from the nucleus and has ...
  • Dust around Herbig Ae/Be stars: IRAS low resolution spectra 
    Bhatt, H. C; Gorti, U (Astronomical Society of India, 1993)
    IRAS low resolution spectra are presented for 17 Herbig Ae/Be stars. The observed spectral characteristics are correlated with reddening E(B-V) and the spectral type of the star. The silicate emission feature at 9.7 ...
  • Dust around R Coronae Borealis Stars. I. Spitzer/Infrared Spectrograph Observations 
    Aníbal García-Hernández, D; Kameswara Rao, N; Lambert, D. L (IOP Publishing, 2011-09-20)
    Spitzer/infrared spectrograph (IRS) spectra from 5 to 37 μm for a complete sample of 31 R Coronae Borealis stars (RCBs) are presented. These spectra are combined with optical and near-infrared photometry of each RCB at ...
  • Dust Around R Coronae Borealis Stars. II. Infrared Emission Features in an H-poor Environment 
    Garcia-Hernandez, D. A; Kameswara Rao, N; Lambert, D. L (IOP Publishing, 2013-08-20)
    Residual Spitzer/Infrared Spectrograph spectra for a sample of 31 R Coronae Borealis (RCB) stars are presented and discussed in terms of narrow emission features superimposed on the quasi-blackbody continuous infrared ...
  • The dust content and radiation fields of sample of galaxies in the ELAIS-N1 field 
    Shalima, P; Gogoi, R; Pathak, A; Misra, R; Gupta, R; Vaidya, D. B (The University of Chicago Press on behalf of the Astronomical Society of the Pacific, 2015-08)
    The Mid-IR colors (F8/F24) of galaxies together with their IR-UV luminosity correlations can be used to get some insight into the relative abundance of the different dust grain populations present in them. The ELAIS-N1 ...
  • Dust envelopes around RV Tauri stars 
    Raveendran, A. V (The Royal Astronomical Society, 1989-06)
    In the IRAS (12)-(25), (25)-(60) color-color diagram, RV Tauri stars are found to populate cooler temperature regions, distinctly different from those occupied by the oxygen and carbon Miras. The IRAS fluxes are consistent ...
  • The dust grains in the coma of Comet West 
    Krishna Swamy, K. S; Shah, G. A (D. Reidel Publishing Co, 1987-07)
    The observed variation of reddening as a function of the heliocentric distance and the spatial variation of reddening within the coma of Comet West in the visual wavelength range have been considered to infer the properties ...
  • Dust in an extragalactic environment : The case of NGC 2907 
    Patil, M. K; Pandey, S. K; Kembhavi, A. K; Singh, M (Astronomical Society of India, 2001)
    We have carried out a detailed CCD surface photometric analysis of the lenticular galaxy NGC 2907, containing multiple dust lanes, with the objective of studying properties of dust in an extragalactic environment. Measurements ...

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