I have been very fortunate to inherit a Criterion Dynamax 8 Astronomical Telescope from my Father. He was given this as a present by my mother back in 1974. It is an 8" Schmidt-Cassegrain Telescope and considered a bit of an antique. I don't think he used it because two of the electrical connections for the Motor Drive were the wrong way round, so it was not possible to get it working without correcting this problem. There are varying reports across the internet on this telescope from good if setup correctly to mostly terrible. Many reporting every possible optical abberation you can think of, and plenty of other uncomplimentary statements!