Father of sidewalk and, I would argue, cheaper astronomy, John Dobson passed away this morning. A big loss to the astro community. He invented the "Dobsonian" telescope mount, which has enabled cheaper telecope construction because the telescope optical tube assemblies could be mounted on a box, lazy-susan mount design. This mount could be made from wood and is a super-simple design allowing easy alt-azimuth movement.
Thank you for your contributions to popular astronomy!