What is an airy disk, and how are they used to identify problems with a telescope? <\/p>

An Airy disk is a bright, circular spot of light formed in the centre of an image.<\/p>\n

It happens as light passes through a circular aperture, such as found on a telescope, and is a result of the light waves being diffracted.<\/p>\n

By aiming a telescope at a bright star, which is essentially a point source of light, centring it in the field of view and then defocusing the star image, close inspection will reveal a series of bright and dark concentric rings.<\/p>\n

By examining the shape of these rings, astronomers are able to identify optical and collimation<\/a> issues in their telescopes.<\/p>\n

You could also do this by constructing your own artificial star<\/a>.<\/p>\n

Have you got a question for Steve? Email your queries to scopedoctor@skyatnightmagazine.com<\/a> and they could be answered in the next issue of BBC Sky at Night Magazine.<\/strong><\/em><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div> <\/body><\/html>\n

","protected":false},"excerpt":{"rendered":"
What is an airy disk, and how are they used to identify problems with a telescope? <\/p>\n","protected":false},"author":24,"featured_media":47759,"template":"","categories":[1],"acf":{"readingTimeMinutes":"< 1"},"uagb_featured_image_src":{"full":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained.jpg",849,849,false],"thumbnail":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained-150x150.jpg",150,150,true],"medium":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained-300x300.jpg",300,300,true],"medium_large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained-768x768.jpg",768,768,true],"large":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained.jpg",800,800,false],"1536x1536":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained.jpg",849,849,false],"2048x2048":["https:\/\/c01.purpledshub.com\/uploads\/sites\/77\/2023\/07\/airy-disks-explained.jpg",849,849,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":"What is an airy disk, and how are they used to identify problems with a telescope?","_links":{"self":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/rss_feed\/47758"}],"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\/47759"}],"wp:attachment":[{"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/media?parent=47758"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/wp-json\/wp\/v2\/categories?post=47758"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}