William Optics 1.25" 90° Erecting Prism with Helical Focuser

William Optics 1.25" 90° Erecting Prism with Helical Focuser

Description:
The William Optics 90° erecting prism corrects both image inversion and mirror-reversal, providing upright and true-orientation views — perfect for terrestrial observation. It features a large BAK4 prism with anti-reflection coatings for optimal brightness and contrast.

A built-in helical focuser allows fine focus adjustment without moving the eyepiece. The internal surfaces are matte-blackened to minimize reflections. The body is crafted from black anodized aluminum and includes a standard 1.25" filter thread.

While excellent for daytime viewing, this prism may occasionally produce a vertical diffraction spike when used for astronomy.

Technical specifications:
– Type: 90° erecting prism
– Size: 1.25"
– Optics: BAK4 prism
– Coating: anti-reflection
– Orientation: true up/down and left/right
– Integrated helical focuser
– Anodized aluminum body
– Threaded for 1.25" filters
– Recommended use: terrestrial
– Weight: not specified

Additional information:
Designed primarily for terrestrial viewing. Compatible with all 1.25" eyepieces and focusers. Not intended for high-resolution astrophotography.