{"id":631,"date":"2014-08-24T23:34:29","date_gmt":"2014-08-24T21:34:29","guid":{"rendered":"http:\/\/freebook.fernglas-astronomie.de\/?page_id=631"},"modified":"2014-08-24T23:34:29","modified_gmt":"2014-08-24T21:34:29","slug":"cetus","status":"publish","type":"page","link":"http:\/\/freebook.fernglas-astronomie.de\/?page_id=631","title":{"rendered":"Cetus"},"content":{"rendered":"<p>The Whale depicts the sea monster Cetus from the tale of Andromeda. The Whale contains few bright stars and is hidden very well in the sky. Johann Elert Bode\u2018s star atlas \u201eUranographia\u201c from 1801 showed on the southern border of the Whale the now forgotten constellation \u201eMachina Electrica\u201c (electricity generator).<\/p>\n<p><strong><em>\u03bf Ceti<\/em><\/strong> is also known as <strong><em>Mira<\/em><\/strong>, \u201cthe Wonderful\u201d. As namesake of the Mira stars, it is one of the most well-known variables. The East-Frisian amateur astronomer David Fabricius was the first to notice a change in brightness with this star, but he thought of it as a onetime event. Only in 1638 Johann Fokkens noticed that the fluctuations take place periodically. Within 331 days, the brightness varies approximately between 3<sup>m<\/sup> and 9<sup>m<\/sup>. The brightness variations of the star are related to changes in its size \u2013 although Mira has only two solar masses, its diameter varies between the 300 and 400 fold solar diameter. In the border regions, there must prevail almost a good vacuum by Earth standards. During the minima, Mira has a surface temperature of only 3,450\u00b0 F (1,900\u00b0 C), which makes it one of the coolest known stars. During the maximums, the temperature rises to 4,500\u00b0 F (2,500\u00b0 C).<\/p>\n<p>The 3.5<sup>m<\/sup> bright <strong><em>\u03c4 Ceti<\/em><\/strong> is a mere 11.5 light-years away and the most sun-like star in our vicinity. Still, it is only half as luminous as our Sun. Visually, nothing distinguishes it from other stars; but in 2012 hints for five planets were discovered. But even in a telescope, \u03c4 Ceti appears as one star among many others. Here the fun in the observation is once again in the knowledge of what you are looking at.<\/p>\n<p>At 8.9<sup>m<\/sup> and an area of 6 \u00d7 7 arcmin, the galaxy <strong><em>M 77<\/em><\/strong> is interesting especially for larger binoculars. It is the brightest member of a group of galaxies in the vicinity of \u03b4 Ceti and can be found about 1\u00b0 east of this 4.1<sup>m<\/sup> bright star. Inside of the galaxy, interstellar gas clouds have been observed which move at a speed of 370 miles per second (600 km\/s) \u2013 they were probably accelerated by an explosion in the core of the galaxy. Its core region is also the source of strong radio emissions. M\u200977 is about 58 million light-years away and thus the most distant Messier object. It is four times more luminous than our own galaxy.<\/p>\n<figure id=\"attachment_356\" class=\"wp-caption aligncenter\" style=\"width: 400px;\"><a href=\"http:\/\/freebook.fernglas-astronomie.de\/wp-content\/uploads\/2014\/04\/M77.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-356\" src=\"http:\/\/freebook.fernglas-astronomie.de\/wp-content\/uploads\/2014\/04\/M77.jpg\" alt=\"Die Galaxie M77 im Walfisch ist das am weitesten entfernte Objekt im Messier-Katalog und im Fernglas ein verwaschenes Sternchen.\" width=\"400\" height=\"266\" srcset=\"http:\/\/freebook.fernglas-astronomie.de\/wp-content\/uploads\/2014\/04\/M77.jpg 400w, http:\/\/freebook.fernglas-astronomie.de\/wp-content\/uploads\/2014\/04\/M77-300x199.jpg 300w\" sizes=\"auto, (max-width: 400px) 100vw, 400px\" \/><\/a><figcaption class=\"wp-caption-text\">M\u200977 in Cetus is the most distant Messier object. In binoculars you can see it only as a fuzzy star.<\/figcaption><\/figure>\n<p>With a diameter of four minutes of arc, the <strong><em>Propeller Nebula NGC 246<\/em><\/strong> is one of the most extensive planetary nebulae. You can see at 10x magnification that it is not a star, but its overall brightness is only 8.0<sup>m<\/sup>, so that it remains an object for larger binoculars. If you can\u2018t use filters, you have to try averted vision.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The Whale depicts the sea monster Cetus from the tale of Andromeda. The Whale contains few bright stars and is hidden very well in the sky. Johann Elert Bode\u2018s star atlas \u201eUranographia\u201c from 1801 showed on the southern border of the Whale the now forgotten constellation \u201eMachina Electrica\u201c (electricity generator). \u03bf Ceti is also known &hellip; <a href=\"http:\/\/freebook.fernglas-astronomie.de\/?page_id=631\" class=\"more-link\"><span class=\"screen-reader-text\">Cetus<\/span> weiterlesen <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":618,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-631","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/pages\/631","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=631"}],"version-history":[{"count":1,"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/pages\/631\/revisions"}],"predecessor-version":[{"id":632,"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/pages\/631\/revisions\/632"}],"up":[{"embeddable":true,"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=\/wp\/v2\/pages\/618"}],"wp:attachment":[{"href":"http:\/\/freebook.fernglas-astronomie.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=631"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}