Until now, orthoscopic and Plössl eyepiece have been the eyepieces of choice for lunar, planetary, and binary star/star cluster observers. Their low number of lenses (four) and air-to-glass surfaces (also four) give visibly better contrast and definition than the more exotic extra wide field eyepieces. A high quality orthoscopic or Plössl eyepiece on a good telescope gives views of Mars, Jupiter, and Saturn that are unforgettable. But even the ortho and Plössl designs can be improved for lunar and planetary use. The TMB Optical® eyepieces are the first long eye relief eyepieces with a comfortably wide field that have the sharpness, contrast, and lack of lateral color and light scatter for planetary observing of the best orthoscopic and Plössl designs. What they dont have is the ortho and Plössls limited eye relief and restricted fields. The six-element TMB Optical® eyepieces provide a substantial 58° field of view with high contrast, a tack sharp view, and surprisingly long eye relief for relatively unvignetted eyeglass use. Read more
TMB Planetary II eyepieces are some of the most respected eyepieces available. They provide exceptionally high power along with very comfortable eye relief making them one of the best eyepieces around. 6 elements and 58 degrees field of view coupled with 14mm eye relief. They are noted for their high contrast and definition because of their high light transmission and minimal light scatter. The eyepiece is brilliant for lunar and planetary work but is also a very capable performer at splitting double stars and showing huge detail in objects such as nebulae and globular clusters.
Ed ~ The eyepiece does indeed provide a very bright and contrasty image, and with a 500mm f5 scope frames the lunar or solar disk perfectly. The downside is without placing the eye exactly at the 'sweetspot' there is a lot of optical vignetting (or 'kidney bean blackout'). The barrel can be unscrewed out slightly to raise the rubber eye guard to get the eye distance just right. A small tip for beginners is to make a large peephole (pencil diameter hole) mask which can be place within the rubber eye guard to position the eye exactly central to the eyepiece.
Another small tip is that cheap 49mm or 48mm photographic filters can fit snugly over the raised rubber eye-shield.