The Prostar 80° UWA 1.25” eyepieces are an economical way to get an ultra-wide angle Apparent Field of View (AFOV) eyepiece.
As with contemporary eyepiece designs, the Prostar 80° UWA 1.25” eyepieces are not a particular design, but a range of eyepieces that all offer an 80° AFOV with the same large eye lens (the lens you look into). Because of the nature of the design of these eyepieces, the eye relief is not as long as some other designs.
The Prostar 80° UWA 1.25” eyepieces offer fully multi-coated lenses with blackened edges to reduce ghosting/internal reflections and improve contrast. They are also threaded to accept 1.25” filters.
The Prostar 80° UWA 1.25” range of eyepieces are best suited to refractors, Cassegrains and slower f/ratio Newtonians.
Note that achromatic refractors show achromatic aberration, and this will be more significant as the eyepiece focal length becomes shorter. To help overcome this blue flaring, a Yellow #12 filter or Baader Fringe Killer filter can be used to reduce this effect.