{"id":28832,"date":"2022-02-05T13:16:49","date_gmt":"2022-02-05T13:16:49","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=104286"},"modified":"2022-02-05T13:27:10","modified_gmt":"2022-02-05T13:27:10","slug":"what-is-the-moon-illusion","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/what-is-the-moon-illusion\/","title":{"rendered":"What is the Moon illusion?"},"content":{"rendered":"

<\/p>

By Patrick Moore\n \t\t<\/p>

Published: Saturday, 05 February 2022 at 12:00 am<\/p>

\n\n

Look for the Moon when it is low to the horizon and you may get the impression that it is unnaturally large \u2013 this is the phenomenon known as the Moon illusion, and it appears to be more pronounced around full Moon<\/a> when the maximum area of its disc is illuminated.<\/p>\n

In reality, the Moon has more or less the same apparent diameter of around 0.5\u00ba, whether it is looming over the horizon or riding high in the sky.<\/p>\n

For more advice, read our guide on how to observe the Moon<\/a>, or have a go at sketching it with our guide on how to draw the Moon<\/a>.<\/strong><\/em><\/p>\n

\""A\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>\n

What causes the Moon illusion?<\/strong><\/h2>\n

One explanation for the Moon illusion arises from our perception of the shape of the celestial sphere above us: instead of a hemisphere, we perceive the sky to be a flattened dome.<\/p>\n

Consequently the lower the Moon is in the sky, the farther away and larger it is perceived to be.<\/p>\n

\""Moon\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Moon rising, Mike Read, Longleat forest, Wiltshire, 25 June 2021. Equipment: Canon 90D DSLR, Sigma 150\u2013600mm lens<\/span><\/figcaption><\/div>\n

When the Moon is high in the sky we conversely perceive it to be closer to us and therefore smaller in apparent size.<\/p>\n

Or perhaps when the Moon is lower in the sky, it appears closer to the landscape and foreground objects such as trees or human-made structures, making it seem comparatively bigger.<\/p>\n

\""Supermoons\"<\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/source><\/picture><\/div>
Credit: Jeff Morgan \/ Getty Images<\/span><\/figcaption><\/div>\n

What ever the reasons for it, few people seem to be immune to the Moon illusion, even though the viewer may be fully aware that for any given evening there is actually no appreciable difference in the Moon\u2019s apparent diameter, regardless of its height above the horizon.<\/p>\n

You can check this for yourself the next time you witness the Moon looking unusually big while it\u2019s low down towards the horizon.<\/p>\n

Stretch your arm out and you\u2019ll find that you can still cover the lunar disc comfortably with your thumb, thus \u2013 momentarily at least \u2013 breaking the illusion.<\/p>\n

Or you could try photographing the Moon<\/a>, capturing one image when it\u2019s close to the horizon and another when it\u2019s high in the sky.<\/p>\n

Keep your zoom settings the same for both photos, then compare them. You\u2019ll see that the apparent size of the Moon hasn\u2019t changed at all. It\u2019s all merely part of the illusion.<\/p><\/body><\/html>\n

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By Patrick Moore Published: Saturday, 05 February 2022 at 12:00 am Look for the Moon when it is low to the horizon and you may get the impression that it is unnaturally large \u2013 this is the phenomenon known as the Moon illusion, and it appears to be more pronounced around full Moon when the […]<\/p>\n","protected":false},"author":24,"featured_media":28833,"template":"","categories":[1],"acf":{"readingTimeMinutes":"3"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion.jpg",1001,720,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion-300x216.jpg",300,216,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion-768x552.jpg",768,552,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion.jpg",800,575,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion.jpg",1001,720,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2022\/02\/what-is-the-moon-illusion.jpg",1001,720,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 Patrick Moore Published: Saturday, 05 February 2022 at 12:00 am Look for the Moon when it is low to the horizon and you may get the impression that it is unnaturally large \u2013 this is the phenomenon known as the Moon illusion, and it appears to be more pronounced around full Moon when the…","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/28832"}],"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\/28833"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=28832"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=28832"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}