Baader AstroSolar® Safety Film OD 5.0 for Telescopes

What is OD 5.0 solar filter film used for?

Baader AstroSolar® Safety Film OD 5.0 is optical filter material for a front-aperture filter placed ahead of a telescope, binocular objective or camera lens. The manufacturer states that it reduces sunlight intensity by 99.999% and is intended for white-light solar observing and photography with additional optics. It shows the solar photosphere and sunspots. Observing prominences and other chromospheric details in H-alpha requires a dedicated H-alpha system.

This category includes individual sheets for DIY filter construction as well as pre-mounted telescope filters. The listed mounted versions include 100 mm and 140 mm models. Check each product description carefully: a sheet size is not the same as a ready-made filter size, and a filter’s nominal size does not replace checking the actual clamping and tube dimensions.

Choose the right option

• Filter sheet: for customers who want to build a stable, correctly fitting filter cell. The sheet alone is not a ready-to-use solar filter. Use only the specified AstroSolar® Safety Film OD 5.0 and follow the manufacturer’s installation instructions.
• Pre-mounted filter: select a version that fits your telescope aperture and mounting surface. Measure and compare the relevant diameters and confirm that the filter can be secured firmly to the tube. It must cover the entire objective opening and stay in place.
• Binoculars or camera: check the instructions for your instrument. Both binocular objectives must be securely filtered. Cover any finder or optical viewfinder that could otherwise be pointed at the Sun.

Important safety instructions

According to the manufacturer, AstroSolar® Safety Film OD 5.0 is only for use as a front filter ahead of the optics. It is not approved for naked-eye viewing or for making eclipse viewers. Never place a solar filter behind the eyepiece. Before every observing session, inspect the film and mount for scratches, pinholes, tears, coating damage and a loose fit. Do not use damaged film, and secure the filter against slipping. Do not leave an unfiltered finder pointed at the Sun. Open-truss telescopes may only be used with this film when the tube is covered.

For direct solar viewing without a telescope or binoculars, use a solar viewer specifically approved for that purpose. AstroSolar® Safety Film OD 5.0 does not meet the standard for such viewers. You can also compare other white-light options such as glass solar filters. For H-alpha observing, see dedicated H-alpha solar telescopes and H-alpha filters.