The more light the telescope takes in, the fainter the objects that can be seen. For that reason, most amateur astronomers build or buy reflecting telescopes. Large mirrors are considerably cheaper to build or buy than large lenses. First, a star in any telescope is still just a point of light. Stars are so far away that even the highest magnification the atmosphere will allow will not show anything more than a point of light.
Constellations require the unaided eye.
Any kind of magnification reduces the field of view to a small fraction of the area of most constellations. The Moon and Planets can be observed well in either refracting or reflecting telescopes. Many open star clusters are best seen in binoculars, again because they cover a wider field than can be seen in most telescopes. Globular star clusters are fainter and are best seen in reflecting scopes, the larger the better. Nebulae are faint and require the light grasp of a reflecting telescope, preferably 8 or bigger.