sextant

A short guide to celestial navigation The CD-Sextant Build your own sextant One of the obstacles to learn and practice celestial navigation is the price and availability of sextants. Even the simplest plastic models cost between US$ 50 and 150 and can only be found in a few specialized stores. This scares interested people away […]

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The Making of Planet Earth – National Geographic Full Documentary

Published on Jun 19, 2013 ❶ HD Documentary Channel: For all your Space, Universe, Science and Technology documentaries! Published on Oct 4, 2013 This edition of COSMIC JOURNEYS explores the still unfolding story of Earth’s past and the light it sheds on the science of climate change today. While that story can tell us about […]

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Μηχανισμός των Αντικυθήρων

More than 21 centuries ago, a mechanism of fabulous ingenuity was created in Greece, a device capable of indicating exactly how the sky would look for decades to come — the position of the moon and sun, lunar phases and even eclipses. But this incredible invention would be drowned in the sea and its secret […]

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The Gregorian calendar

The Gregorian calendar, also called the Western calendar and the Christian calendar, is internationally the most widely accepted civil calendar.[1][2][3] It was introduced by Pope Gregory XIII, after whom the calendar was named, by a decree signed on 24 February 1582; the decree, apapal bull, is known by its opening words, Inter gravissimas.[4] The Gregorian calendar was adopted initially by the Catholic countries of Europe, […]

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NASA | Computer Model Shows a Disk Galaxy’s Life History

Published on Oct 19, 2012 This cosmological simulation follows the development of a single disk galaxy over about 13.5 billion years, from shortly after the Big Bang to the present time. Colors indicate old stars (red), young stars (white and bright blue) and the distribution of gas density (pale blue); the view is 300,000 light-years […]

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voyage across the cosmos

National Geographic presents the first accurate non-stop voyage from Earth to the edge of the Universe using a single, unbroken shot through the use of spectacular CGI (Computer-Generated Imagery) technology. Building on images taken from the Hubble telescope, Journey to the Edge of the Universe explores the science and history behind the distant celestial bodies […]

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