Dobsonian telescopes are a type of reflector telescope that uses a simple design and a large aperture to provide clear views of astronomical objects.
The telescopes are named after their inventor, John Dobson, who developed the design in the 1960s.
Dobsonian telescopes typically have a simple mount that allows the telescope to rotate in all directions.
The telescope's optics are usually a simple Newtonian reflector, which uses a concave mirror to collect light and a flat secondary mirror to reflect the light into the eyepiece.
Dobsonian telescopes typically have a large aperture, which allows them to collect more light than smaller telescopes and provides a brighter image.
Dobsonians telescopes are popular among amateur astronomers because they are relatively inexpensive and easy to use.