{"id":23181,"date":"2021-08-24T08:50:03","date_gmt":"2021-08-24T08:50:03","guid":{"rendered":"https:\/\/www.skyatnightmagazine.com\/?p=98685"},"modified":"2021-08-24T09:04:09","modified_gmt":"2021-08-24T09:04:09","slug":"a-guide-to-the-moons-rupes-recta","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/bbcskyatnight\/rss_feed\/a-guide-to-the-moons-rupes-recta\/","title":{"rendered":"A guide to the Moon\u2019s Rupes Recta"},"content":{"rendered":"

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

Published: Tuesday, 24 August 2021 at 12:00 am<\/p>

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Rupes Recta, also known as the \u2018Straight Wall\u2019 is a most curious linear feature. Roughly on a vertical centreline of the Moon\u2019s face, about one-third of the way up from the southern pole, it is easily seen with a small telescope when the lighting is right.<\/p>\n

And here, lighting is very important indeed.\u00a0When the Sun is at the right angle, the Straight Wall becomes quite obvious.<\/p>\n

For more info on lunar observing, read our guides on how to observe the Moon<\/a> and the best features on the Moon<\/a>.<\/strong><\/em><\/p>\n

\""Rupes\"<\/div>
Rupes Recta, the \u2018Straight Wall\u2019, is neither straight nor a wall \u2013 it\u2019s a linear fault in the Moon\u2019s surface. Credit: Pete Lawrence<\/span><\/figcaption><\/div>\n

One day after the first quarter Moon<\/a>, the rising Sun makes it cast a dark shadow to the west, giving the impression it must be a massive, high cliff.<\/p>\n

As the Moon reaches its last quarter phase, the Sun\u2019s light illuminates the Straight Wall from the other side, causing it to appear bright.<\/p>\n

The reason for this difference in appearance is that the Straight Wall isn\u2019t a wall or cliff at all \u2013 it\u2019s a slope.<\/p>\n

Facts about Rupes Recta<\/strong><\/h1>\n