DESC: In some cases, shorter is better. This is one of them. The catadioptric feature has a correcting lens built into the optical tube that extends the focal length without the need for an extra-long tube. Another plus... it's mounted on a fully motorized dual axis German equatorial mount. Hey, if it can run on it's own power, it's got my vote. Frees me up to put my energy elsewhere. Plus, the dual axis control center hand box lets you scan the skies without looking away from the eyepiece. You can stay focused on the cosmos without distraction.