{"id":21522,"date":"2021-08-03T09:59:02","date_gmt":"2021-08-03T09:59:02","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=98669"},"modified":"2021-08-03T09:33:27","modified_gmt":"2021-08-03T09:33:27","slug":"how-to-see-the-lunar-x-and-lunar-v","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/how-to-see-the-lunar-x-and-lunar-v\/","title":{"rendered":"How to see the Lunar X and Lunar V"},"content":{"rendered":"

<\/p>

By Pete Lawrence\n \t\t<\/p>

Published: Tuesday, 03 August 2021 at 12:00 am<\/p>

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The way the light from the Sun plays with features on the lunar surface is fascinating. When the light falls on areas of elevation or relief, shadows are created that give observers the impression they\u2019re seeing amazingly pointed mountains, suspended illuminated arcs and immense canyons.<\/p>\n

Some of this light produces patterns that are reminiscent of more modest fare.\u00a0The Lunar X is one example, appearing as large letter X suspended against the lunar night.<\/p>\n

Such creations are known as clair-obscur<\/a> effects, literally \u2018clear-dark\u2019, referring to the play of light that tricks the eye into seeing something that isn\u2019t really there.<\/p>\n

Read our guides on how to observe the Moon<\/a> and how to photograph the Moon<\/a><\/strong><\/em><\/p>\n

\""Lunar\"<\/div>
Lunar X by Steve Farrington, Blackpool, UK. Equipment: Nikon D7200, Sigma 150-600mm.<\/span><\/figcaption><\/div>\n

There are many clair-obscur effects visible on the Moon and most, like the Lunar X, are transient. To see them you have to observe within the short window when they are visible.<\/p>\n

In the case of the Lunar X, it takes approximately 2.3 hours for the feature to form<\/span>.<\/p>\n

Low to medium magnification works best as this is less likely to emphasise the roughness created by smaller craters along the arms of the X.<\/p>\n

Once formed, the X remains visible for about an hour, taking a further 70 minutes to fade back into the lunar surface as it slowly illuminates. In total, the observing window lasts for 4.5 hours.<\/p>\n

Facts about the Lunar X<\/strong><\/h1>\n