Telescope filter Celestron CE94107 Black Aluminium 3.18 cm

The Celestron CE94107 Black Aluminium 3.18 cm telescope filter is a compact accessory engineered to improve visual observations through a range of compatible telescopes. Constructed with a black aluminium cell and a 3.18 cm outer diameter, the filter is designed to fit eyepieces or adapters with matching threads or holders. Its optical element is intended to enhance contrast and clarity when observing the Moon, planets, and brighter deep-sky objects by reducing glare and improving definition.

Advantages

The aluminium cell provides durable, lightweight housing that resists corrosion and maintains secure threading for stable attachment. The 3.18 cm outer diameter makes the filter suitable for many common eyepiece sizes and diagonal adapters. By selectively managing incoming light, the filter helps reduce scattered light and improves the perceived sharpness of surface details on planetary and lunar targets.

Suitable for

• Visual planetary observation to enhance contrast of surface features
• Lunar viewing to reduce glare and reveal finer details
• Use with eyepieces and diagonals compatible with a 3.18 cm outer diameter filter
• Casual backyard stargazing and targeted observing sessions

Key specifications

• Material: black aluminium cell for durability and lightweight handling
• Outer diameter: 3.18 cm to match compatible eyepiece or adapter fittings
• Optical function: contrast and glare reduction for improved visual clarity
• Mounting: threaded cell designed for secure attachment to compatible telescope accessories

How to use

Attach the filter by screwing it into the threaded end of a compatible eyepiece, diagonal, or adapter until it is snug; avoid over-tightening. Insert the eyepiece into the focuser as you would for normal observation. Allow the telescope to thermally stabilize for best optical performance, and adjust focus after the filter is in place. For multi-step setups, fit the filter between the eyepiece and diagonal or as recommended by your eyepiece manufacturer.

Usage recommendations

Clean optical surfaces with a soft blower and microfiber cloth; avoid touching the glass with fingers. Store the filter in a protective case when not in use to prevent scratches and keep threads free of debris. Use the filter primarily for bright targets where contrast enhancement and glare reduction improve detail visibility.