Baader ASTF 120 mm OD 5.0 Solar Filter for Telescopes

Baader ASTF 120 mm OD 5.0 Solar Filter for Telescopes

DESCRIPTION

The Baader ASTF 120 mm solar filter features the AstroSolar Safety Film OD 5.0, allowing for safe and detailed solar observation and photography. Unlike homemade drum-tight filters, this one is mounted stress-free inside a thermally regulated frame to preserve image sharpness across a temperature range from -30 °C to +50 °C.

The filter is built with a precision-matched injection-molded plastic ring and aluminum frame to ensure no mechanical stress affects the film. This floating design maintains diffraction-limited optical performance in all thermal conditions.

Two sets of centering pins (10 mm and 20 mm diameter, 38 mm long) allow installation on a wide range of tube diameters. Three Velcro safety straps are included to secure the filter. Printed index scales next to each adjustment opening enable fast, repeatable centering.

The front aluminum ring reflects heat and protects the film from sharp edges. Designed for use at magnifications up to 120x, this filter delivers excellent image clarity, ideal for sunspot detail and full-disc imaging.

TECHNICAL SPECIFICATIONS

Type: solar filter
Model: ASTF 120 mm
Item no.: 2459312
Filter film: Baader AstroSolar Safety OD 5.0
Optical density: 5.0
Transmission: white light
Mount: stress-free, thermal-compensated housing
Clear aperture: 120 mm
Outer diameter: 210 mm
Weight: 0.17 kg
Internal clamping range (10 mm pins): 170–200 mm
Internal clamping range (20 mm pins): 180–210 mm
External clamping range (10 mm pins): 150–180 mm
External clamping range (20 mm pins): 140–170 mm
Attachment: 3 centering pins, safety straps, index markings
Included: complete filter, 6 pins (3 × 10 mm, 3 × 20 mm), Velcro straps, sealing caps, secure shipping box