If one has a ST-X guider, what advantage is there to potentially getting an AO-X? Do they both run together at the same time? Dale
Yes, they work together. The STX Guider provides the guide sensor, which is used by the AO-X. The AO-X provides fast and highly repeatable guiding. With a bright enough guide star you can guide 10X per second. Depending on conditions this can improve your star spot size noticeably. Also if your mount has problems with PE, backlash, stiction, etc., it completely eliminates that. See http://diffractionlimited.com/product/ao-x/