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Radar determination of the Astronomical Unit

Published online by Cambridge University Press:  14 August 2015

Irwin Shapiro*
Affiliation:
Lincoln Laboratory(1), Massachusetts Institute of Technology, Lexington, Mass., U. S. A.

Abstract

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A comprehensive review is given of the Earth-Venus measurements made with the Lincoln Laboratory Millstone radar in 1959 and 1961. The time-delay and Doppler shift data yield a value for the Astronomical Unit of 499.0052 ± 0.001 light-sec. Using 299 792.5 km/s for the speed of light leads to an AU of 149 598 000 ± 300 km. With the radius of Earth taken as 6 378.15 km, the solar parallax then becomes 8″.79416 ± 0″.00002. This value is consistent with measurements made at various other laboratories to about one part in 105.

Résumé. — L'auteur donne une description complète des mesures de la distance Terre-Vénus faites par le radar Millstone en 1959-1961. Le temps de parcours des ondes et le décalage Doppler donnent, pour l'unité astronomique 499,0052 ± 0,001 secondes de lumière, soit 149 598 000 ± 300 km avec c = 299 792,5 km/s. Avec un rayon terrestre de 6 378,15 km, la parallaxe solaire devient 8,79416 ± 0,00002. Ces résultats s'accordent avec ceux d'autres laboratoires à 10−5 près.

Zusammenfassung. — Es wird ein vollständiger Überblick über die Bestimmungen der Entfernung Erde-Venus gegeben, die mit dem Millstone-Radargerät des Lincoln Laboratory in den Jahren 1959 und 1961 durchgeführt wurden. Die Messungen der Laufzeit und der Doppler-Verschiebung ergeben einen Wert von 499,0052 ± 0,001 Lichtsekunden für die Astronomische Einheit; das entspricht 149 598 000 ± 300 km bei einer Lichtgeschwindigkeit von 299 792,5 km. Bei Annahme des Erdradius zu 6 378,15 km wird die Sonnenparallaxe dann 8,79416 ± 0,00002. Dieser Wert stimmt auf etwa 1 : 105 mit den Messungen an verschiedenen anderen Laboratorien überein.

Резюме. — Автор подробно описывает измерения расстояния между Землей и Венерой при помощи радара Мильстон в 1959 и 1961гг. Метод времени распространения волн также как и метод смещения частот по Допплеру, дали следущие значения астрономической единицы: 499,0052±0,001 секунд света, то-есть, пологая с 299 792,5 км/с, 149 598 000 ± 300 км. Принимая 6 378,15 км для радмуса Земли, получаем для солнечного параллакса, 8"79416±000001. Эти результаты согласуются с точностью до 10 −5 с результатами других лабораторий.

Type
Research Article
Copyright
Copyright © CNRS 1965 

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