A cardboard tube holds the optics and the mount is constructed of particleboard. The movement is smoothed by Teflon pads riding on Formica. The first Dobsonians used paint stir sticks for the spider and a particleboard disc covered with bubble-pak for the primary mirror holder. This inexpensive approach was needed since John was building telescopes while living as a monk and had to scrounge the materials, having taken a vow of poverty. What this approach ultimately accomplished was move amateur telescope makers into a new realm of larger apertures, opening a whole new field of objects that could be observed.
Eyepieces provide a focused image for the eye that the brain then interprets.
As such, eyepieces are the most important telescope accessory, providing the critical link between the telescope and the eye. The choice of an eyepiece is a very personal one, depending on such things as desired field of view, object under observation, the telescope, location, sky conditions and observer experience. With so many variables it is not possible to choose eyepieces based on the telescope alone, but here are some considerations worth noting. These include such eyepiece designs as the Nagler and Panoptic by TeleVue, the SMC by Pentax and similar designs. Two inch eyepieces are preferred for wide, low-power fields of view, minimizing vignetting, or edge of field light loss.