When it comes to Schmidt Cassegrain mirror telescopes, Celestron is the expert. Despite the extremely compact design, they have a long focal length, with which the Moon, planets and deep sky objects can be wonderfully observed. This also makes them very easy to transport and so are perfect for visual observing on the move. The EdgeHD version is particularly suitable for astrophotography, and produces images that are, edge-to-edge, completely undistorted and sharp.
OTA stands for for optical tube assembly. This means you get a powerful optical tube in a modern design without a mount.