Takahashi
The fourth iteration of the FSQ-106, the EDX4 is a quadruplet astrograph refractor with a focal length of 530mm and an aperature of 106mm, yielding an f/5 optical beast.
In my setup I removed the stock focuser and replaced it with a 3.5” NiteCrawler, which you can check out at MoonLite’s site (trust me- Ron’s stuff is MUCH better than the website!)