757 research outputs found

    Technical support systems for manned space astronomy Semiannual report for period ending 1 Oct. 1968

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    Development of film cassett for astronomical photography in space environment, and image dissectors as display devices for astronomical experimentation from manned spacecraf

    The Last Days

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    Properties of the redshift

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    Central to any analysis of dynamical systems, or large scale motion, is the interpretation of redshifts of galaxies as classical Doppler velocity shifts. This is a testable assumption and for many years evidence has accumulated that is inconsistent with the assumption. Here, the authors review recent evidence suggesting systematic radial dependence and temporal variation of redshifts

    On the investigations of galaxy redshift periodicity

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    In this article we present a historical review of study of the redshift periodicity of galaxies, starting from the first works performed in the seventies of the twentieth century until the present day. We discuss the observational data and methods used, showing in which cases the discretization of redshifts was observed. We conclude that galaxy redshift periodisation is an effect which can really exist. We also discussed the redshift discretization in two different structures: the Local Group of galaxies and the Hercules Supercluster. Contrary to the previous studies we consider all galaxies which can be regarded as a structure member disregarding the accuracy of velocity measurements. We applied the power spectrum analysis using the Hann function for weighting, together with the jackknife error estimator. In both the structures we found weak effects of redshift periodisation.Comment: 10 pages, 4 figures, to be published in Part. and Nucl. Lett. 200

    Introduction

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    Research in far ultraviolet filtering for space optical systems

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    Design and fabrication of multilayer interference filters for ultraviole

    Control of static electricity in 35mm film transports under vacuum conditions

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    Control of static electricity in transporting 35mm film in vacuu

    Results from computer program for analyzing scattered light suppression systems for large space telescope

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    A computer program was developed which has the ability to analyze the performance of most light suppression systems so as to predict the amount of scattered light which will reach the image plane for various conditions of unwanted light input from the sun, earth, or moon. This program was used to analyze three different configurations of the large space telescope (LST): an LST with a truncated sunshield, an LST with an extended cylindrical sunshield, and an LST with a conical sunshield which is tilted upwards. The computer program gives the user detailed information as to the paths taken by the unwanted stray light to reach the image plane, and pinpoints those portions of the light suppression system which contribute most of the stray light, so that areas requiring improvements are evident. Certain design guide lines were formulated for any light suppression system selected for the LST, and one which meets these requirements (the tilted sunshade) is described in detail

    Weak redshift discretisation in the Local Group of Galaxies?

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    We discuss the distribution of radial velocities of galaxies belonging to the Local Group. Two independent samples of galaxies as well as several methods of reduction from the heliocentric to the galactocentric radial velocities are explored. We applied the power spectrum analysis using the Hann function as a weighting method, together with the jackknife error estimation. We performed a detailed analysis of this approach. The distribution of galaxy redshifts seems to be non-random. An excess of galaxies with radial velocities of 24kms1\sim 24 {km} \cdot {s}^{-1} and 36kms1\sim 36 {km} \cdot {s}^{-1} is detected, but the effect is statistically weak. Only one peak for radial velocities of 24kms1\sim 24 {km} \cdot {s}^{-1} seems to be confirmed at the confidence level of 95%.Comment: 23 pages 7 figures Astronomische Nachrichten accepte
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