TMB PLANETARY 9mm 58° 1,25"
This TMB Planetary II eyepiece series is from TMB Optical, the company founded by noted apochromatic refractor designer Thomas M. Back to produce state-of-the-art premium optics.
The TMB Planetary II has been optimized to show maximum contrast, detail, and definition with a wide variety of telescope types and focal ratios when viewing bright objects such as the Moon and planets. It has very high light transmission and contrast, plus minimal lateral color and light scatter. These combine to provide exceptional high power observing, both on and off axis, with long focal length refractors, reflectors, and catadioptric scopes under average or better seeing conditions.
Eye relief, varying between 10mm and 14mm, is quite good for eyepieces with such short focal lengths. Vignetting will only be moderate for those who must wear eyeglasses while observing. This usually won’t be a problem when using the TMB Planetary II eyepiece on the kinds of objects for which it was optimized – planets, binary stars, etc. – as these small objects are generally kept in the center of the eyepiece field, where your eyesight is sharpest.
For Dobsonian users and others without tracking drives, the very low lateral color 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.
5mm model shown.