A type of high level cloud that is ver thin and causes a halo effect around earths sun and moon is called?

A type of high-level cloud that is very thin and often causes a halo effect around the Earth's sun and moon is called cirrostratus. These clouds are composed of ice crystals and can create a translucent veil, leading to the optical phenomenon known as a halo, which appears as a circular ring of light around celestial bodies. Cirrostratus clouds typically indicate that precipitation may be on the way.