{"id":623,"date":"2026-01-28T05:33:21","date_gmt":"2026-01-28T05:33:21","guid":{"rendered":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/?p=623"},"modified":"2026-04-13T04:34:23","modified_gmt":"2026-04-13T04:34:23","slug":"optical-phenomena-in-antarctica-sun-halo","status":"publish","type":"post","link":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/2026\/01\/28\/optical-phenomena-in-antarctica-sun-halo\/","title":{"rendered":"Optical Phenomena in Antarctica: Sun Halo"},"content":{"rendered":"\n<p>This part two in a series on optical phenomenon that we&#8217;ve experienced here in Antarctica. The previous post was on Fata Morgana. This post will describe sun halos.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" src=\"http:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-content\/uploads\/sites\/73\/2026\/04\/EC14EF4C-F3B7-4998-9DAA-BD2327EE7D5B_1_105_c-1.jpeg\" alt=\"\" class=\"wp-image-628\" \/><\/figure>\n\n\n\n<p><em>Above: Sun halo seen on the Ross Ice Shelf. The mountain just below it is Mt. Erebus, an active volcano.<\/em><\/p>\n\n\n\n<p>Sun halos are most commonly found in cold regions, such as high altitude mountains or polar regions. They are seen as a circle of light around the sun. Sun halos are caused by light refracting through ice crystals. High altitude clouds or extremely low temperatures create thin layers of suspended ice crystals. Light from the sun refracts through these ice crystals, and depending on their shape and orientation, different optical effects are formed. The image above shows a 22\u00ba circular halo. The halo forms at an angular distance of 22\u00ba from the sun because the hexagonal shape of the ice crystals refracts light at a minimum angle of about 22\u00ba. Just as there can be a double rainbow, it is possible for there to be an additional circular halo at 46\u00ba, though I haven\u2019t been lucky enough to experience one yet. Circular halos can be formed around the moon as well through the same process, causing an eerie lunar halo. Hopefully we&#8217;ll get to see lunar halos this winter in the constant darkness!<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"5712\" height=\"4284\" src=\"http:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-content\/uploads\/sites\/73\/2026\/04\/IMG_6903.jpg\" alt=\"\" class=\"wp-image-627\" \/><\/figure>\n\n\n\n<p><em>Above: Sun halo seen outside the Arrival Heights laboratory<\/em>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This part two in a series on optical phenomenon that we&#8217;ve experienced here in Antarctica. The previous post was on Fata Morgana. This post will describe sun halos. Above: Sun halo seen on the Ross Ice Shelf. The mountain just below it is Mt. Erebus, an active volcano. Sun halos are most commonly found in&hellip; <a class=\"read-more\" href=\"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/2026\/01\/28\/optical-phenomena-in-antarctica-sun-halo\/\">Read More<\/a><\/p>\n","protected":false},"author":215,"featured_media":627,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-623","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized"],"jetpack_featured_media_url":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-content\/uploads\/sites\/73\/2026\/04\/IMG_6903.jpg","publishpress_future_action":{"enabled":false,"date":"2026-09-02 14:03:10","action":"change-status","newStatus":"draft","terms":[],"taxonomy":"category","extraData":[]},"publishpress_future_workflow_manual_trigger":{"enabledWorkflows":[]},"_links":{"self":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts\/623","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/users\/215"}],"replies":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/comments?post=623"}],"version-history":[{"count":3,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts\/623\/revisions"}],"predecessor-version":[{"id":649,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/posts\/623\/revisions\/649"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/media\/627"}],"wp:attachment":[{"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/media?parent=623"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/categories?post=623"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ciresblogs.colorado.edu\/lidarexploration\/wp-json\/wp\/v2\/tags?post=623"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}