My next major decision involves size. The important measure is actually the diameter of the telescope, because that determines how much light the telescope gathers. The major trade-off here is portability. The bigger the telescope, the harder it is to pop into a car and drive into the country. The last big decision I have to make concerns the mounting on which the telescope sits.
Fancy scopes have what is called an equatorial mount.
When setting them up, you point the mount in the direction of the north star and a motor turns the scope in time with the earth so that it follows objects across the sky. Some expensive scopes even have computers that can aim at particular objects. They point in the direction you point them. The image moves out of view within a minute or so as the Earth turns. But it stays in the eyepiece long enough to get a good look.