4 research outputs found
The Measurement of Solar Diameter and Limb Darkening Function with the Eclipse Observations
The Total Solar Irradiance varies over a solar cycle of 11 years and maybe
over cycles with longer period. Is the solar diameter variable over time too?
We introduce a new method to perform high resolution astrometry of the solar
diameter from the ground, through the observations of eclipses by reconsidering
the definition of the solar edge. A discussion of the solar diameter and its
variations must be linked to the Limb Darkening Function (LDF) using the
luminosity evolution of a Baily's Bead and the profile of the lunar limb
available from satellite data. This approach unifies the definition of solar
edge with LDF inflection point for eclipses and drift-scan or heliometric
methods. The method proposed is applied for the videos of the eclipse in 15
January 2010 recorded in Uganda and in India. The result shows light at least
0.85 arcsec beyond the inflection point, and this suggests to reconsider the
evaluations of the historical eclipses made with naked eye.Comment: 16 pages, 11 figures, accepted in Solar Physics. arXiv admin note:
text overlap with arXiv:astro-ph/0601109 by other author
Shock wave physics and detonation physics – a stimulus for the emergence of numerous new branches in science and engineering
In the period of the Cold War (1945−1991), Shock Wave Physics and Detonation Physics
(SWP&DP) – until the beginning of WWII mostly confined to gas dynamics, high-speed
aerodynamics, and military technology (such as aero- and terminal ballistics, armor
construction, chemical explosions, supersonic gun, and other firearms developments) –
quickly developed into a large interdisciplinary field by its own. This rapid expansion
was driven by an enormous financial support and two efficient feedbacks: the
Terminal Ballistic Cycle and the Research &
Development Cycle. Basic knowledge in SWP&DP, initially gained
in the Classic Period (from 1808) and further extended in the
Post-Classic Period (from the 1930s to present), is now increasingly
used also in other branches of Science and Engineering (S&E). However, also
independent S&E branches developed, based upon the fundamentals of SWP&DP,
many of those developments will be addressed (see Tab. 2). Thus, shock wave and detonation
phenomena are now studied within an enormous range of dimensions, covering microscopic,
macroscopic, and cosmic dimensions as well as enormous time spans ranging from
nano-/picosecond shock durations (such as produced by ultra-short laser pulses) to shock
durations that continue for centuries (such as blast waves emitted from ancient supernova
explosions). This paper reviews these developments from a historical perspective