Results 121 to 130 of about 2,143 (164)

Calibration challenges for low frequency radio astronomy

2011 XXXth URSI General Assembly and Scientific Symposium, 2011
A major challenge for all high resolution low frequency radio astronomy is measuring and removing the effects of the ionosphere. The isoplanatic patch size for frequencies below a few hundred MHz is generally much smaller than the field of view. In addition, aperture arrays have beams on the sky which vary dramatically with observing geometry.
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Solar radio astronomy at low frequencies

2008
Powerful radio radiation often originates from the Sun at decametric and kilometric wavelengths. Radiation from the quiet Sun is produced by the thermal mechanism of bremsstrahlung, and radio bursts of several kinds are produced by the non-thermal mechanisms of plasma radiation and, rarely, gyrosynchrotron radiation.
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UWB active antenna array for low frequency radio astronomy

2012 6th International Conference on Ultrawideband and Ultrashort Impulse Signals, 2012
The decameter wavelength range is of interest for radio astronomy at the present time. Construction of giant low-frequency radio telescopes has been planned and is being carried out in European Union (Low Frequency Array - LOFAR), USA (Long Wavelength Array - LWA) and in Ukraine (Giant Ukrainian Radio Telescope - GURT).
A. A. Konovalenko, I. S. Falkovich, A. A. Gridin, P. L. Tokarsky, S. N. Yerin   +4 more
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Low-frequency radio astronomy engineering in Western Australia

2017 IEEE Radio and Antenna Days of the Indian Ocean (RADIO), 2017
I will discuss low-frequency radio astronomy engineering efforts underway in Western Australia. We carry out this work through the International Centre for Radio Astronomy Research (ICRAR)/Curtin University. The frequency range of interest is ∼50 to ∼350 MHz, which is the Low-Frequency Square Kilometre Array (SKA-Low) frequency band.
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Introduction to Low Frequency Radio Astronomy

2018
Radio astronomy began at low (ν ≪ 300 MHz) frequencies, but until recently has traditionally been dominated by higher frequency work. With the advent of a new generation of low frequency interferometers and the anticipation of the low-frequency component of the Square Kilometre Array (SKA), the field is experiencing a rebirth. This introductory chapter
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The radio environment for a space-based low-frequency radio astronomy instrument

2019 IEEE Aerospace Conference, 2019
Opening the last frequency window for radio astronomy in the sub - 30 MHz region includes a few challenges. First of all, at frequencies below 30 MHz the Earths ionosphere severely distorts radio waves originating from celestial sources, and it completely blocks radio waves below 10 MHz.
Bentum, Mark J., Boonstra, Albert Jan, Horlings, Wouter, van Vugt, Pieter   +3 more
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Very low frequency radio astronomy from the moon

2008
Lunar development is virtually certain to occur in the next 10–20 years. Very low frequency radio astronomy observations can and should begin with the first lander. A modest yet powerful near-side array should be built if backside development will be substantially delayed. A major backside array should be constructed when technology and funding permit.
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High time resolution radio astronomy with low-frequency interferometric arrays

2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS), 2014
High time resolution applications of radio astronomy including pulsars and fast radio bursts are proving to be incredibly scientifically rewarding in terms of the depth and breadth of new physics and astrophysics they unveil. While the use of large single-dish type instruments has been dominating the field over the past decades, with the emergence of ...
N. D. R. Bhat, S. M. Ord, S. E. Tremblay, S. J. Tingay, A. A. Deshpande, W. van Straten   +5 more
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Solar system, low frequency radio astronomy from the moon

Advances in Space Research, 1994
Radio astronomy, particularly radio astronomy at low frequencies (< 100 MHz) is becoming more and more difficult to operate from Earth-based observatories because of the proliferation of manmade interferences. At frequencies lower than 10 MHz, observations are rarely possible,or impossible, because of the opacity of the terrestial ionosphere.
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Low frequency radio astronomy through an artificially created ionospheric window

Nature, 1975
THE ionosphere presents a nearly impenetrable barrier for ground-based decametric (3–30 MHz) radioastronomical observations, though a few valiant efforts have been made under special conditions to reach frequencies near 1 MHz (ref. 1).
MICHAEL D. PAPAGIANNIS, MICHAEL MENDILLO
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