Cracking open the mystery of how many bubbles are in a glass of beer

Cracking open the mystery of how many bubbles are in a glass of beer

Eyepiece sun filters were once commonly supplied with imported telescopes and consist of a piece of dark glass mounted in a cell that screws into the bottom of an eyepiece. The heat from the Sun concentrated by a telescope can shatter these filters without warning, making them very dangerous

Glass injection molding