A rare celestial triangle is visible to stargazers this week when a slender crescent moon aligns with planets Jupiter and Venus near bright stars Castor and Pollux. The event occurs on August 20, just before dawn in London.
In the constellation of Gemini, the twins, the celestial grouping will be seen, accompanied by the majestic Orion, the hunter, as it rises to the east. As a waning crescent moon, with only 11% of its surface illuminated, it appears fainter than Venus and Jupiter.
The event is best observed in London on both August 20 mornings at 04:00 and 05:00 BST, or the night after when the moon will be almost fully dark. During this time, Mercury may also become visible as the Sun rises over the eastern horizon.
Source: https://www.theguardian.com/science/2025/aug/18/starwatch-moon-jupiter-and-venus-centre-of-exquisite-gathering