Sinus Iridum

The Bay of Rainbows, a spectacular semicircular bay on the northwestern edge of Mare Imbrium.

Visual Description

Sinus Iridum appeared as a beautiful semicircular bay indenting the northwestern shore of Mare Imbrium. The bay was bordered by the Montes Jura mountain range creating a dramatic arc. When the terminator crosses the feature, the mountains catch sunlight first, creating the spectacular “Jeweled Handle” effect. The bay floor was smooth and dark, continuous with Mare Imbrium.

Notable Features

• Beautiful semicircular bay, 236 km across
• Bordered by Montes Jura mountains
• Famous “Jeweled Handle” effect at sunrise
• Smooth, dark lava-filled floor
• Part of larger Imbrium Basin

Notes

• Name means “Bay of Rainbows”
• Best observed 9-11 days after new moon
• The Jeweled Handle is a spectacular sight
• Coordinates: 44.1°N, 31.5°W
• Luna 17 (Lunokhod 1) landed here in 1970