When humidity rises, water vapor absorbs and scatters light, reducing the transparency of the night sky. This lowers contrast, making faint stars and nebulae harder to capture sharply.
Humidity also increases atmospheric turbulence, causing light to bend unpredictably and blur your images. Additionally, moisture can cause subtle color shifts and soften fine details by diffusing light.
To get crisp, high-contrast photos, managing humidity or choosing low-humidity nights is essential.