Absolute Flux Distribution of the SDSS Standard BD +17°4708

2004 ◽  
Vol 128 (6) ◽  
pp. 3053-3060 ◽  
Author(s):  
R. C. Bohlin ◽  
R. L. Gilliland
1996 ◽  
Vol 112 ◽  
pp. 307 ◽  
Author(s):  
Luis Colina ◽  
Ralph C. Bohlin ◽  
Fiorella Castelli

1970 ◽  
Vol 1 (8) ◽  
pp. 378-379 ◽  
Author(s):  
J. Davis ◽  
R. J. Webb

The angular diameter of a star, combined with observed stellar fluxes in absolute units, allows the absolute fluxes emitted at the surface of the star to be calculated and thus provides a stringent test of model atmosphere predictions. Furthermore, if the flux distribution is observed at all wavelengths contributing significantly to the net flux, an empirical effective temperature can be found. Sufficient data are now available for Sirius (αCMa) to be studied in this way.


2008 ◽  
Vol 135 (3) ◽  
pp. 1092-1098 ◽  
Author(s):  
R. C. Bohlin ◽  
D. Koester

2017 ◽  
Vol 24 (5) ◽  
pp. 939-953 ◽  
Author(s):  
Andrew W. Stevenson ◽  
Francesca Di Lillo

It is shown that an extensive set of accurate ionization-chamber measurements with a primary polychromatic synchrotron X-ray beam transmitted through various filter combinations/thicknesses can be used to quite effectively estimate the absolute flux distribution. The basic technique is simple but the `inversion' of the raw data to extract the flux distribution is a fundamentally ill-posed problem. It is demonstrated, using data collected at the Imaging and Medical Beamline (IMBL) of the Australian Synchrotron, that the absolute flux can be quickly and reliably estimated if a suitable choice of filters is made. Results are presented as a function of the magnetic field (from 1.40 to 4.00 T) of the superconducting multi-pole wiggler insertion device installed at IMBL. A non-linear least-squares refinement of the data is used to estimate the incident flux distribution and then comparison is made with calculations from the programsSPECTRA,XOPandspec.exe. The technique described is important not only in estimating flux itself but also for a variety of other, derived, X-ray properties such as beam quality, power density and absorbed-dose rate. The applicability of the technique with a monochromatic X-ray beam for which there is significant harmonic contamination is also demonstrated. Whilst absolute results can also be derived in this monochromatic beam case, relative (integrated) flux values are sufficient for our primary aim of establishing reliable determinations of the percentages of the various harmonic components.


1981 ◽  
Vol 101 (11) ◽  
pp. 698-698
Author(s):  
Itsuya Muta ◽  
Eiichi Mukai ◽  
Masaru Yagi

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 509
Author(s):  
Lodovica Valetti ◽  
Francesca Floris ◽  
Anna Pellegrino

The technological innovation in the field of lighting and the need to reduce energy consumption connected to public lighting are leading many municipalities to undertake the renewal of public lighting systems, by replacing the existing luminaires with LED technologies. This renovation process is usually aimed at increasing energy efficiency and reducing maintenance costs, whist improving the lighting performance. To achieve these results, the new luminaires are often characterised by a luminous flux distribution much more downward oriented, which may remarkably influence and alter the perception of the night image of the sites. In this study the implications of the renovation of public lighting systems in terms of lighting and energy performance as well as the effects relating to the alteration of the night image, in historical contexts characterized by significant landscape value, are analysed. Results, along with demonstrating the positive effect that more sustainable and energy efficient lighting systems may have on the lighting performance and energy consumptions of public lighting systems, evidences the impact they may have on the alteration of the nocturnal image.


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