Inspired by the lens cap by @SDHayes, I completely designed this a snap-fit main mirror cover for the Hadley telescope from scratch. It is durable, so nothing falling onto the main mirror will damage it. It is not attached to the rods, so it will work with imperial or metric versions of the Hadley telescope. It is a pretty tight fit, but I like it that way, so if I transport the Hadley telescope, the cover will not move and leave the mirror exposed.