{"id":30839,"date":"2022-04-06T08:15:56","date_gmt":"2022-04-06T08:15:56","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=106829"},"modified":"2022-04-06T08:35:08","modified_gmt":"2022-04-06T08:35:08","slug":"what-causes-a-ring-or-halo-around-the-moon","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/what-causes-a-ring-or-halo-around-the-moon\/","title":{"rendered":"What causes a ring or halo around the Moon?"},"content":{"rendered":"

<\/p>

By Garry Hunt\n \t\t<\/p>

Published: Wednesday, 06 April 2022 at 12:00 am<\/p>

\n\n

So you\u2019ve looked up at the Moon tonight and noticed there\u2019s a ring or \u2018halo\u2019 around it. What could be causing this?<\/p>\n

The ring around the Moon \u2013 or \u2018lunar halo\u2019 is caused by the refraction of moonlight from ice crystals in the upper atmosphere.<\/p>\n

Sign up to the BBC Sky at Night Magazine e-newsletter<\/a> for weekly Moon phases delivered to your email inbox, or read our guide on how to observe the Moon<\/a>.<\/strong><\/em><\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Cirrus clouds are found at high altitudes and resemble tufts of hair or cotton wool. Credit: Doug Armand \/ Getty Images<\/span><\/figcaption><\/div>\n

Cirrus clouds, at a height of 6,000m (20,000ft) or more in the atmosphere, contain tiny ice crystals that originate from the freezing of water droplets.<\/p>\n

These ice crystals refract, or bend, light just like a camera lens. It is the shape of the ice crystals that focuses the light into a halo around the Moon.<\/p>\n

Since the ice crystals are normally all hexagonal, the Moon\u2019s ring is almost always the same size; it has a diameter of 22\u00ba.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Moon and Mars inside a lunar halo, by Andrew Morl, Grassholme Observatory, County Durham, 30 October 2020. Equipment: Nikon D7200 DSLR, Sigma 8\u201316mm lens<\/span><\/figcaption><\/div>\n

Sometimes it is also possible to detect a second ring, 44\u00ba in diameter.<\/p>\n

In folklore, a ring around the Moon forecasts bad weather on the way, and in many cases this may be true.<\/p>\n

The ice crystals that produce the halo and their attendant cirrus clouds normally precede a warm front by one or two days.<\/p>\n

\"""\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
A halo around the Moon captured by Mohammed Aissa Moussa from Ghardaia, Algeria. Equipment: Canon EOS 5D Mark II DSRL camera, 15mm fisheye lens.<\/span><\/figcaption><\/div>\n

Typically, a warm front will be associated with a low-pressure system, which is commonly referred to as a storm.<\/p>\n

Some folk tales say that the number of stars within the Moon\u2019s halo indicates the number of days before bad weather will arrive. Give it a try next time you see a halo.<\/p><\/body><\/html>\n

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By Garry Hunt Published: Wednesday, 06 April 2022 at 12:00 am So you\u2019ve looked up at the Moon tonight and noticed there\u2019s a ring or \u2018halo\u2019 around it. What could be causing this? The ring around the Moon \u2013 or \u2018lunar halo\u2019 is caused by the refraction of moonlight from ice crystals in the upper […]<\/p>\n","protected":false},"author":24,"featured_media":30840,"template":"","categories":[1],"acf":{"readingTimeMinutes":"2"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon.jpg",1079,720,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon-300x200.jpg",300,200,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon-768x512.jpg",768,512,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon-1024x683.jpg",800,534,true],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon.jpg",1079,720,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/04\/what-causes-a-ring-or-halo-around-the-moon.jpg",1079,720,false]},"uagb_author_info":{"display_name":"importmanagerhub@sprylab.com","author_link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/author\/importmanagerhubsprylab-com\/"},"uagb_comment_info":0,"uagb_excerpt":"By Garry Hunt Published: Wednesday, 06 April 2022 at 12:00 am So you\u2019ve looked up at the Moon tonight and noticed there\u2019s a ring or \u2018halo\u2019 around it. What could be causing this? The ring around the Moon \u2013 or \u2018lunar halo\u2019 is caused by the refraction of moonlight from ice crystals in the upper…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/30839"}],"collection":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed"}],"about":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/types\/rss_feed"}],"author":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/users\/24"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media\/30840"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=30839"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=30839"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}