Brandon is a brand name of VernonScope, and is applied to a variety of products, including a well-established line of eyepieces. Several of the short- to medium focal-length Brandon eyepieces are advertised as orthoscopics, yet they appear upon disassembly to resemble Plossls. They use four lenses in an unsymmetrical duplet formulation designed by Chester Brandon, one of the designers of the top-secret Norden bombsight, which played an important role in World War II.

Brandon eyepieces are a popular choice of professional astronomers worldwide. VernonScope estimates that over one million Brandons in various incarnations and focal lengths have been produced since their introduction in the early 1940s. Designed for medium to high power use with any telescope at focal ratios down to f/4, they are very sharp at the center (although somewhat less so at the edges) and ideally suited to lunar, planetary, star cluster, and binary star observing. They have excellent color correction and very low astigmatism, with very minor field curvature and ghosting. They are fully coated, but not multicoated, in order to reduce a phenomenon known as "narrow angle light scatter" that is sometimes seen in multicoated optics. This scatter shows as a loss of contrast and subtle details within bright objects such as Venus, Mars, and Jupiter. It also shows as a significant difference in the background darkness immediately surrounding a bright object, which is especially important for double-star observing. Brandons are accordingly noted for their exceptional contrast and extremely dark background, two reasons why Questar has been using them in their ultra-premium Maksutov-Cassegrain scopes since 1971. They have moderately wide apparent fields of view, of about 45°.

Brandons are threaded for Vernonscope filters only. The use of standard eyepiece color or nebula filters requires adapter 3405. They have rubber eyecups that roll down for eyeglass use, although their eye relief is quite short in the shorter focal lengths. Brandons are the sharpest design currently available in a 1.25" barrel size for eyepiece projection photography

The Refractor Brandon Group: http://tech.groups.yahoo.com/group/refractorbrandongroup/?v=1&t=search&ch=web&pub=groups&sec=group&slk=1
YOUTUBE: http://www.youtube.com/watch?v=MWLNux2SKFA

Clave (Or Clavé) eyepieces ?

Claves have their place but Brandons are better.

While any eyepiece can serve as a “planetary” eyepiece, an eyepiece which is best able to perform on lunar or planetary targets should naturally optimize its performance around those attributes which are peculiar to the target being observed. A planet as an observing target, when compared to the many other celestial targets available to the observer, has many attributes which are unique and can all occur simultaneously within the field of view. Arguably, the resulting major attributes of the primary planets (i.e., Jupiter, Saturn, Mars, Venus), and the importance these attributes become relative to selecting a planetary eyepiece, can be summarized as follows:
1 – Very Bright
Becomes important for the eyepiece to control internal reflections, glare, flare, scatter, and lateral color as these problems are usually accentuated by a very bright object either in the field of view, or just outside the field of view.
2 – Small in Angular Size
Becomes important for the eyepiece to be available in short focal lengths so higher magnifications are available without adding more components like a Barlow which may not be to the optimum level as your planetary eyepiece.
3 – Rich in Both Very High Contrast & Very Low Contrast Features
Becomes important for the eyepiece to have excellent transmission and contrast with minimal scatter so low contrast features are more easily visible and high contrast features are more brilliantly defined to impart a well defined three dimensional effect.

4 – Has Colored Features which are Easily Observable
Becomes important for the eyepiece to have excellent transmission so sufficient light is available to activate the color receptors in your eyes and a neutral image tone to preserve the true colors.
5 – Has Satellites (i.e., moons)
Becomes important for the eyepiece to have high transmission to better see dim satellites, high contrast so satellite shadows on a planet surface are more stark, and low scatter with a sharp field stop so dim moons are more easily detectable if you need to hide the planet behind the field stop and still have a field of view free from reflections and scatter in order to detect dim satellites close to the planet.

Great post.