A Razor-Thin 0.59% ‘Split’ Crescent Moon

An extremely thin waxing crescent Moon (0.59% illumination, 0.19′ thickness), with an age of 17 hours 05 minutes, elongation + 8.82° was observed about 15 minutes after sunset from the United Kingdom—more often known for cloudy skies. The Moon was located at a low altitude of +5.32°, with the Sun at −3.27°. Despite some atmospheric extinction near the horizon, the crescent remained visible for nearly 28 minutes.

Initially, it appeared as a short, razor-thin arc rather than a full crescent, resembling a fine, sharp edge reflecting sunlight. Noticeable variations in brightness were seen along its limb, and at first sight, this uneven brightness gave the impression of a “split crescent moon,” as described by the observers.

As the sky darkened, the arc extended and grew more distinct, but soon began to dim as it descended toward the lower horizon. The full arc remained detectable down to an altitude of about +1.12°, after which it faded from view.

As a roaming crescent hunter, moments like this are a trophy and unforgettable. While such thin crescents are often seen by a single observer, being able to share and confirm the sighting with four others made it even more meaningful—though I know I will always long to witness such a delicate sight again.

Nikon D750
Nikon 200-500mm f5.6E ED VR AF-S

Touched in Photoshop to show the crescent moon.