Telescope filter Baader Planetarium 2458305A Black 1.25 inch

The Baader Planetarium 2458305A Black 1.25 inch telescope filter is a colour-neutral accessory designed to fit standard 1.25" eyepieces. It is intended to improve contrast and reduce stray light during visual observations, helping to reveal finer planetary details and subtle surface features on bright objects. The slim, threaded cell allows insertion into eyepieces or visual back adaptors without significant vignetting, maintaining the optical path for typical amateur telescopes.

Advantages

This 1.25 inch filter enhances image contrast by reducing scattered light and reflections, delivering a clearer view of planetary disks and high-contrast targets. Its black, neutral appearance preserves natural colours while improving definition. The mechanical construction is compact and threaded for secure attachment to eyepieces, and the filter thickness is optimised to minimise interference with focus and eye relief.

Suitable for

• Planetary observation (Moon, Jupiter, Saturn, Mars)
• High-contrast features on bright deep-sky objects
• Visual astronomy sessions with 1.25" eyepieces
• Projects requiring reduced glare and improved detail

Key specifications

• Filter diameter: 1.25 inch (fits standard 1.25" eyepieces)
• Optical type: neutral contrast-enhancing filter
• Appearance: black, non-tinted transmission aimed at preserving natural colour
• Mechanical: slim threaded cell for eyepiece attachment
• Intended use: visual observing to improve contrast on bright targets

How to use

Thread the filter into the 1.25" female filter threads of compatible eyepieces or into a 1.25" adapter on the telescope visual back. Confirm the filter is firmly seated to avoid accidental rotation during viewing. Observe through the eyepiece as usual; the filter will reduce stray light and increase apparent contrast without requiring changes to telescope focus in most setups. Remove or replace the filter when switching between faint deep-sky targets and bright planetary observing as needed.

Usage recommendations

Use the filter on bright objects and planetary targets to maximise contrast improvement. Store the filter in a protective case when not in use to prevent dust and scratches. Combine with suitable eyepiece magnification and stable mount tracking for best results.