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This block began on 15:12, 27 August 2023 and has been set to finish on: <b>15:12, 27 August 2028</b>.</td></tr> </tbody></table> <div style="text-align: center;"><big> </big><p><big><b>You are not blocked from reading pages, only from changing or creating them.</b></big><br /> If you have just clicked a <span style="color:#BA0000; text-decoration:underline;">red link</span>, you were blocked from creating a new page as no article on that topic is there yet. </p> </div> If you think you were not blocked fairly, you may make unblock requests or file appeals at <a href="https://meta.wikimedia.org/wiki/Steward_requests/Global" class="extiw" title="meta:Steward requests/Global">meta:Steward requests/Global</a>.</div></div><hr /> <p>You can view and copy the source of this page. </p><textarea readonly="" accesskey="," id="wpTextbox1" cols="80" rows="25" style="" class="mw-editfont-monospace" lang="en" dir="ltr" name="wpTextbox1">[[File:Planispherical astrolabe mg 7100.jpg|right|thumb|An astrolabe from the 16th century]] The '''astrolabe''' is a tool using the positions of the [[star]]s or [[sun]]. It was formerly used in [[navigation]] to help explorers and sailors figure out where they were. They found their distance north and south of the [[equator]] by measuring the distance of the sun and stars above the [[horizon]]. [[Astronomy|Astronomers]] used other kinds of astrolabes, usually larger ones. An early astrolabe was made in the Hellenistic world in 150 BC. It is often attributed to [[Hipparchus]]. The astrolabe was a marriage of the [[planisphere]] (a star chart analog computing instrument) and [[dioptra]] (a tool to measure [[angle]]s). It was a [[calculator]] able to work out many kinds of problems in [[astronomy]]. Theon of Alexandria wrote a complex book on the astrolabe. Lewis says that [[Ptolemy]] used an astrolabe to make the astronomical [[observation]]s recorded in the ''Tetrabiblos''.<ref>Lewis M.J.T. 2001. ''Surveying instruments of Greece and Rome''. Cambridge University Press.</ref><ref>Evans, James 1998. ''The history and practice of ancient astronomy''. Oxford University Press, p155. "The astrolabe was in fact an invention of the ancient Greeks". {{ISBN|0-19-509539-1}}</ref><ref>Krebs, Robert E. & Carolyn A. 2003. ''Groundbreaking scientific experiments, inventions, and discoveries of the ancient world''. Greenwood Press, p56. "It is generally accepted that Greek astrologers, in either the first or second centuries BC, invented the ''astrolabe'', an instrument that measures the altitude of stars and planets above the horizon. Some historians attribute its invention to [[Hipparchus]]"</ref> == Related pages == *[[Antikythera mechanism]] == References == {{reflist}} {{sci-stub}} [[Category:Measuring tools]] </textarea><div class="templatesUsed"><div class="mw-templatesUsedExplanation"><p>Templates used on this page: </p></div><ul> <li><a href="/wiki/Template:Catalog_lookup_link" title="Template:Catalog lookup link">Template:Catalog lookup link</a> (<a href="/w/index.php?title=Template:Catalog_lookup_link&action=edit" title="Template:Catalog lookup link">change</a>) </li><li><a href="/wiki/Template:Error-small" title="Template:Error-small">Template:Error-small</a> (<a href="/w/index.php?title=Template:Error-small&action=edit" title="Template:Error-small">change</a>) </li><li><a href="/wiki/Template:ISBN" title="Template:ISBN">Template:ISBN</a> (<a href="/w/index.php?title=Template:ISBN&action=edit" title="Template:ISBN">view source</a>) (protected)</li><li><a href="/wiki/Template:Main_other" 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