{"id":21996,"date":"2020-10-16T12:41:34","date_gmt":"2020-10-16T11:41:34","guid":{"rendered":"https:\/\/www.astronom.cz\/horalek\/?p=21996"},"modified":"2020-10-16T18:06:26","modified_gmt":"2020-10-16T17:06:26","slug":"mirror-to-the-past","status":"publish","type":"post","link":"https:\/\/www.petrhoralek.com\/?p=21996","title":{"rendered":"Mirror to the Past"},"content":{"rendered":"
\"Mirror<\/a>

Mirror to the Past<\/p><\/div>\n

This mosaic is not about what you might think on the first look. There is more–photographic mirror to the past when we were able to see the Southern Cross from higher latitudes of the northern hemisphere! But let’s start with the basics.<\/p>\n

Do you think the view to the sky was always the same? Not at all! One of the significant factors of skyview change though the time is Earth’s Axial precession<\/a>, the gradual shift in the orientation of Earth’s axis of rotation in a cycle of approximately 25,772 years. As result of that the visibility of particular parts and objects of the sky was different from one particular place or better the same latitude of Earth. Let’s demonstrate it on this unusual mosaic featuring the sky view from two different sites chosen for their appropriate simulation effect.<\/p>\n

While on the top is situation of night sky taken in May 2020 from Runina<\/a>, Slovak Republic (49 degrees north), bottom skyview was taken in April 2019 from Maldivian island Soneva Fushi<\/a> (5 degrees north). The bottom part then shows what could be seen almost 8000 years ago from the same latitude as nowadays over Slovakia. The year 5964 B.C. was chosen for the similar position of Jupiter and Saturn in the sky like in 2019 when the bottom panorama was taken. Images were taken in time corresponding to same sky situation (so top part on 21st May around 22:10 UTC while the bottom part on 10th April part on 0:30 UTC). Of course, both are real panoramatic photographs taken by both living photographers and so the simulation doesn’t show also change of stars positions<\/a> due to their physical movement in the sky during last 8000 years.<\/p>\n

\"Mirror<\/a>

Mirror to the Past – Annotated<\/p><\/div>\n

Annotated version reveals positions of the North Celestial Pole<\/a> in 2020 A.C. (top) and 5964 B.C. (bottom). Demostration shows the majestic constellation Scorpius<\/a>, central Milky Way or even the mentioned Southern Cross<\/a> were well visible from northern hemisphere 8000 years ago and well known “Summer Triangle<\/a>” was much longer visible during (star Vega was circumpolar unlike Deneb nowadays). Both images were taken with same camera type (Canon 6D BCF modified), similar lenses (28 mm top, 24 mm bottom), same aperture (2.2), ISO (10000) and exposure time of single fragments of panoramas (15 seconds). Of course, due to precession, the current summer sky was best visible sooner, from November to July (while now it is from April to October). <\/p>\n

Both panoramas were taken from dark sky places where even airglow can be seen. Author of top panorama is Tom\u00e1\u0161 Slovinsk\u00fd<\/a>, bottom one Petr Hor\u00e1lek.<\/p>\n","protected":false},"excerpt":{"rendered":"

This mosaic is not about what you might think on the first look. There is more–photographic mirror to the past when we were able to see the Southern Cross from higher latitudes of the northern hemisphere! But let’s start with the basics. Do you think the view to the sky was always the same? Not…
Read more<\/a><\/p>\n","protected":false},"author":1,"featured_media":21997,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[8,7,1],"tags":[],"class_list":["post-21996","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-atmospheric-phenomena","category-landscape","category-milky-way"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=\/wp\/v2\/posts\/21996","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=21996"}],"version-history":[{"count":0,"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=\/wp\/v2\/posts\/21996\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=\/wp\/v2\/media\/21997"}],"wp:attachment":[{"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=21996"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=21996"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.petrhoralek.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=21996"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}