The PF-80ED-A's 1.25" diameter eyepiece specification allows less compacting of the light shaft produced by the objective lens, and thus a larger final image with superior depth perception. Any great 1.25" eyepiece can be used, from Pentax themselves to elite telescope manufacturers' eyepieces such as Meade, Celestron, Vixen, and of course Tele Vue. The PF-80ED has a focal length of 518mm.
Price: $1674.95 from Camera House