Absolute Photometry of the Light of the Night Sky

Absolute Photometry of the Light of the Night Sky PDF

Author: Franklin Evans Roach

Publisher:

Published: 1964

Total Pages: 632

ISBN-13:

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A study is presented of one year of systematic zenith observations made with similar photometers at two observing stations:Haleakala (latitude N 20.7 degrees) and Fritz Peak (latitude N 39.9 degrees).It is shown that, for an effec * tive wavelength of 5300 A, there is a change of intensity with sidereal time (and therefore right ascension) due to three components:(1) integrated starlight, (2) zodiacal light, and (3) airglow continuum. Quantitative separation of the components is made.A critical comparison is made with some earlier investigations with particular reference to the problem of the galactic light.(Author).

At the Crossroads of the Earth and the Sky

At the Crossroads of the Earth and the Sky PDF

Author: Gary Urton

Publisher: University of Texas Press

Published: 2013-12-18

Total Pages: 247

ISBN-13: 0292790511

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Above Misminay, the sky also is so divided by the alternation of the two axes of the Milky Way passing through the zenith. This mirror-image quadri-partition of terrestrial and celestial spheres is such that a point within one of the quarters of the earth is related to a point within the corresponding celestial quarter. The transition between the earth and the sky occurs at the horizon, where sacred mountains are related to topographic and celestial features. Based on fieldwork in Misminay, Peru, Gary Urton details a cosmology in which the Milky Way is central. This is the first study that provides a description and analysis of the astronomical and cosmological system in a contemporary community in the Americas. Separate chapters take up the sun, the moon, meteorological phenomena, the stars, and the planets. Star-to-star constellations, the "animal" dark-cloud constellations that cut through the Milky Way, and certain twilight- and midnight-zenith stars are analyzed in terms of their spatial and temporal integration within an indigenous cosmological framework. Urton breaks new ground by demonstrating the indigenous merging of such forms of "precise knowledge" as astronomy, meteorology, agriculture, and the correlation of astronomical and biological cycles within a single calendar system. More than sixty diagrams clarify this Quechua system of astronomy and relate it to more familiar principles of Western astronomy and cosmology.

Asteroseismology

Asteroseismology PDF

Author: C. Aerts

Publisher: Springer Science & Business Media

Published: 2010-01-19

Total Pages: 872

ISBN-13: 1402058039

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Understanding the stars is the bedrock of modern astrophysics. Stars are the source of life. The chemical enrichment of our Milky Way and of the Universe withallelementsheavierthanlithiumoriginatesintheinteriorsofstars.Stars arethe tracersofthe dynamics ofthe Universe,gravitationallyimplying much more than meets the eye. Stars ionize the interstellar medium and re-ionized the early intergalactic medium. Understanding stellar structure and evolution is fundamental. While stellar structure and evolution are understood in general terms, we lack important physical ingredients, despite extensive research during recent decades.Classicalspectroscopy,photometry,astrometryandinterferometryof stars have traditionally been used as observational constraints to deduce the internal stellar physics. Unfortunately, these types of observations only allow the tuning of the basic common physics laws under stellar conditions with relatively poor precision. The situation is even more worrisome for unknown aspects of the physics and dynamics in stars. These are usually dealt with by using parameterised descriptions of, e.g., the treatments of convection, rotation,angularmomentumtransport,theequationofstate,atomicdi?usion andsettlingofelements,magneto-hydrodynamicalprocesses,andmore.There is a dearth of observational constraints on these processes, thus solar values areoftenassignedtothem.Yetitishardtoimaginethatonesetofparameters is appropriate for the vast range of stars.

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