TMB 4.5mm Planetary Premium Eyepiece

This 4.5mm Planetary eyepiece is from TMB Optical, the company founded by noted apochromatic refractor designer Thomas M. Back to produce state-of-the-art premium optics. This eyepiece offers a truly premium performance at an amazingly low price!

The 4.5mm TMB Planetary has been optimized to show maximum contrast, detail, and definition when viewing bright objects such as the Moon and planets, both on and off axis. This eyepiece features fully multi-coated (FMC) optics and exhibits very high light transmission and contrast, plus minimal chromatic aberation and light scatter. These combine to provide exceptional high power observing with all refractors, reflectors, and catadioptric scopes when the seeing conditions allow.

This eyepiece provides 333x (about 42x per inch of aperture) with an 8" SCT, about the practical maximum magnification possible under good to very good seeing conditions. Eye relief, at 15mm, is excellent for an eyepiece with such a short focal length. Vignetting will only be moderate for those who must wear eyeglasses while observing, although this won't be a problem when viewing the kinds of objects for which it was optimized - planets, binary stars, etc. - when these small objects are kept in the center of the eyepiece field, where your eyesight is sharpest.

For Dobsonian users and others without tracking drives, the very low chromatic and other aberrations allow a planet to drift across the entire 58° field while still being sharp and having high contrast, thereby maximizing observing time. While the eyepiece is optimized for observing subtle lunar and planetary detail, the eyepiece's observing virtues work equally well for splitting binary stars, resolving compact globular clusters, etc.

Specifications:

• Apparent field of view: 58°
• Eye relief: 15mm
• Focal Length: 4.5mm
• Barrel Size: 1.25"