Very high-resolution observations of the radio sources NRAO 150, OJ 287, 3C 273, M87, 1633 + 38, BL Lacertae, and 3C 454.3

1977 ◽  
Vol 211 ◽  
pp. 658 ◽  
Author(s):  
K. I. Kellermann ◽  
D. B. Shaffer ◽  
G. H. Purcell ◽  
I. I. K. Pauliny-Toth ◽  
E. Preuss ◽  
...  
Keyword(s):  
High Resolution ◽  
Radio Sources ◽  
Bl Lacertae ◽  
Very High

Very High Resolution Analysis of the Dynamics of a Coronal Plasmoid

1994 ◽  
Vol 144 ◽  
pp. 593-596
Author(s):  
O. Bouchard ◽  
S. Koutchmy ◽  
L. November ◽  
J.-C. Vial ◽  
J. B. Zirker
Keyword(s):  
High Resolution ◽  
Solar Eclipse ◽  
Total Solar Eclipse ◽  
Field Of View ◽  
Small Field ◽  
High Resolution Analysis ◽  
Ccd Observations ◽  
Resolution Analysis ◽  
Very High ◽  
Small Field Of View

AbstractWe present the results of the analysis of a movie taken over a small field of view in the intermediate corona at a spatial resolution of 0.5“, a temporal resolution of 1 s and a spectral passband of 7 nm. These CCD observations were made at the prime focus of the 3.6 m aperture CFHT telescope during the 1991 total solar eclipse.

The Heights of Solar Radio Sources at 1424 MHz and 696 MHz

1969 ◽  
Vol 1 (5) ◽  
pp. 192-194 ◽  
Author(s):  
D. G. Cole ◽  
R. F. Mullaly
Keyword(s):  
Solar Activity ◽  
High Resolution ◽  
Solar Disk ◽  
Previous Investigation ◽  
Solar Radio ◽  
Radio Sources ◽  
Grating Interferometer ◽  
Maximum Solar Activity

The heights of solar radio sources at 1424 MHz and 696 MHz have been measured during the years 1965 and 1966. Solar activity at this time was near minimum. The number of radio sources appearing on the solar disk rarely exceeded three at any time and it thus was possible to resolve the majority of these with a high resolution grating interferometer. Many of the previous height measurements at these frequencies have been made near times of maximum solar activity and the confusion of sources within the beam has limited their accuracy. The number of sources studied here is quite considerably higher than in any previous investigation at these frequencies, and the period of observation has been continuous.

Three-dimensional fault geometry and kinematics of the 2008 M 7.1 Yutian earthquake revealed by very-high resolution satellite stereo imagery

2019 ◽  
Vol 232 ◽  
pp. 111300
Author(s):  
Xiaogang Song ◽  
Nana Han ◽  
Xinjian Shan ◽  
Chisheng Wang ◽  
Yingfeng Zhang ◽  
...  
Keyword(s):  
High Resolution ◽  
Three Dimensional ◽  
Fault Geometry ◽  
Stereo Imagery ◽  
Very High ◽  
Geometry And Kinematics

scholarly journals Object Oriented Classification for Mapping Mixed and Pure Forest Stands Using Very-High Resolution Imagery

2021 ◽  
Vol 13 (13) ◽  
pp. 2508
Author(s):  
Loredana Oreti ◽  
Diego Giuliarelli ◽  
Antonio Tomao ◽  
Anna Barbati
Keyword(s):  
High Resolution ◽  
Spatial Scales ◽  
Parametric Method ◽  
Mixed Forest ◽  
Mixed Stands ◽  
Mapping Unit ◽  
Mixed Forests ◽  
High Resolution Imagery ◽  
Very High Resolution Imagery ◽  
Very High

The importance of mixed forests is increasingly recognized on a scientific level, due to their greater productivity and efficiency in resource use, compared to pure stands. However, a reliable quantification of the actual spatial extent of mixed stands on a fine spatial scale is still lacking. Indeed, classification and mapping of mixed populations, especially with semi-automatic procedures, has been a challenging issue up to date. The main objective of this study is to evaluate the potential of Object-Based Image Analysis (OBIA) and Very-High-Resolution imagery (VHR) to detect and map mixed forests of broadleaves and coniferous trees with a Minimum Mapping Unit (MMU) of 500 m2. This study evaluates segmentation-based classification paired with non-parametric method K- nearest-neighbors (K-NN), trained with a dataset independent from the validation one. The forest area mapped as mixed forest canopies in the study area amounts to 11%, with an overall accuracy being equal to 85% and K of 0.78. Better levels of user and producer accuracies (85–93%) are reached in conifer and broadleaved dominated stands. The study findings demonstrate that the very high resolution images (0.20 m of spatial resolutions) can be reliably used to detect the fine-grained pattern of rare mixed forests, thus supporting the monitoring and management of forest resources also on fine spatial scales.

scholarly journals High-resolution VLA low radio frequency observations of the Perseus cluster: radio lobes, mini-halo, and bent-jet radio galaxies

2020 ◽  
Vol 499 (4) ◽  
pp. 5791-5805
Author(s):  
M Gendron-Marsolais ◽  
J Hlavacek-Larrondo ◽  
R J van Weeren ◽  
L Rudnick ◽  
T E Clarke ◽  
...  
Keyword(s):  
High Resolution ◽  
Dynamic Range ◽  
Galaxy Cluster ◽  
High Dynamic Range ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Nearby Galaxy ◽  
Cluster Galaxy ◽  
Ngc 1275 ◽  
Perseus Cluster

ABSTRACT We present the first high-resolution 230–470 MHz map of the Perseus cluster obtained with the Karl G. Jansky Very Large Array. The high dynamic range and resolution achieved have allowed the identification of previously unknown structures in this nearby galaxy cluster. New hints of sub-structures appear in the inner radio lobes of the brightest cluster galaxy NGC 1275. The spurs of radio emission extending into the outer X-ray cavities, inflated by past nuclear outbursts, are seen for the first time at these frequencies, consistent with spectral aging. Beyond NGC 1275, we also analyse complex radio sources harboured in the cluster. Two new distinct, narrowly collimated jets are visible in IC 310, consistent with a highly projected narrow-angle tail radio galaxy infalling into the cluster. We show how this is in agreement with its blazar-like behaviour, implying that blazars and bent-jet radio galaxies are not mutually exclusive. We report the presence of filamentary structures across the entire tail of NGC 1265, including two new pairs of long filaments in the faintest bent extension of the tail. Such filaments have been seen in other cluster radio sources such as relics and radio lobes, indicating that there may be a fundamental connection between all these radio structures. We resolve the very narrow and straight tail of CR 15 without indication of double jets, so that the interpretation of such head–tail sources is yet unclear. Finally, we note that only the brightest western parts of the mini-halo remain, near NGC 1272 and its bent double jets.

An Approach for Building Rooftop Border Extraction from Very High-Resolution Satellite Images

2021 ◽  
pp. 1-11
Author(s):  
Yasser Mostafa ◽  
Mahmoud Nokrashy O. Ali ◽  
Faten Mostafa ◽  
Mohamed Yousef
Keyword(s):  
High Resolution ◽  
Satellite Images ◽  
High Resolution Satellite Images ◽  
Very High
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