Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2022 October 10
The featured image shows a broad landscape in Turkey with many images
of the Moon in different phases tracing out doubled figure eight on the sky.
Please see the explanation for more detailed information.

A Double Lunar Analemma over Turkey
Image Credit & Copyright: Betul Turksoy

Explanation: An analemma is that figure-8 curve you get when you mark the position of the Sun at the same time each day for one year. But the trick to imaging an analemma of the Moon is to wait bit longer. On average the Moon returns to the same position in the sky about 50 minutes and 29 seconds later each day. So photograph the Moon 50 minutes 29 seconds later on successive days. Over one lunation or lunar month it will trace out an analemma-like curve as the Moon's actual position wanders due to its tilted and elliptical orbit. Since the featured image was taken over two months, it actually shows a double lunar analemma. Crescent lunar phases too thin and faint to capture around the New moon are missing. The two months the persistent astrophotographer chose were during a good stretch of weather during July and August, and the location was Kayseri, Turkey

Tomorrow's picture: pelican jets

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