Atmospheric seeing describes how steady and clear the air is for astronomical observations. High humidity adds water vapor to the atmosphere, which increases light scattering and creates turbulent air pockets.
This turbulence causes stars to twinkle more intensely and makes images less sharp. Moisture also creates thermal gradients—local temperature differences—that worsen atmospheric instability.
For astrophotographers, this means that humid nights often come with poorer seeing conditions, making it harder to capture fine details in celestial objects.
Understanding how humidity impacts seeing helps you choose better nights for shooting and adjust your techniques to minimize distortion.
