MA 4mm (Pre-owned)

A 4mm eyepiece is an ultra-short focal length eyepiece that provides very high power magnifications, making it best suited for observing planets and the Moon on shorter focal length telescopes.

Some key aspects of a 4mm eyepiece include:

• Sharp Images: These eyepieces produce sharp images, especially on the axis, making them well-suited for planetary observations
• Eye Relief: This is the distance between the rear element of the eyepiece and the observer's pupil, where the entire field of view can be seen. Longer eye relief provides a more enjoyable viewing experience, particularly for those who wear glasses
• Exit Pupil: This is the size of the light cone at the eye relief position. Since our dark-adapted pupil is never larger than 7mm, any exit pupil size above this level is wasted