Is the sky translucent

Answer 1

The sky, or the atmosphere, is actually transparent, not translucent. It's true that clouds, smoke or ash, pollution, fog, haze,..., you get the picture, all contribute to limit or block our vision, but by and large the sky, the atmosphere, is actually transparent. One can see clearly through it. Translucent has a few qualifiers. One is that light can get through, just the same as with transparent materials. But another is that objects viewed through something translucent are indistinct due to diffusion or scattering of the light so that the image cannot be clearly resolved. When weather or other adverse natural phenomena and man's negative contributions are not in play in a way that puts things in the air (in the sky), one can watch a ball game from the upper deck, can see a taller multistory building or a big grain elevator several miles away, or an airplane in flight even further out. And all this with the only restriction on one's ability to make out details being the visual limits of the eye itself. Lastly, who has not marveled at the wonders of the moon and stars when we have occasion to see them on a night where the sky is free of weather obstacles and the bi-products of humans. The stars twinkle just a bit because of slight changes in the density of the many miles of air overhead, but they are quite visible. And lovely.

Answer 2

Window is transparent if made of glass

it is opaque if made of wood