Baader AstroSolar® ClearWhite Safety Filter Film OD 5.1, 50 cm x 50 cm

Baader AstroSolar® ClearWhite Safety Filter Film OD 5.1

The Baader AstroSolar® ClearWhite Safety Film OD 5.1 is a high-quality, double-sided metallized solar filter film designed for direct solar observation as well as for constructing front-mounted objective filters for telescopes, binoculars, spotting scopes, and camera lenses.

The film has an optical density of OD 5.1 and reduces the intensity of sunlight by approximately 99.9992%, corresponding to a reduction factor of about 125000. It complies with the applicable transmittance requirements of EN ISO 12312-2:2015 for filters intended for direct observation of the sun.

Compared to the previous AstroSolar® Safety Film OD 5.0, the new ClearWhite version provides an even clearer, whiter solar image along with a slightly higher optical density. Sunspots, granulation, and fine structures of the photosphere can be seen sharply and richly contrasted when used with suitable optical equipment.

Clear white solar image with high optical quality

AstroSolar® ClearWhite Safety Film OD 5.1 was developed to provide a particularly neutral, clear white solar image. Undesirable bluish or orange color casts, which may occur with simpler solar filters, are largely avoided.

The film is manufactured from a special streak-free and bubble-free substrate and achieves an optical quality comparable to high-quality plane-parallel glass filters despite a thickness of only 0.012 mm. The material is not ordinary "Mylar" and was developed for exceptionally high uniformity and optical purity.

The double-sided coating ensures especially uniform filter performance and reduces the effect of isolated microscopic irregularities in the metallization. A single layer of AstroSolar® ClearWhite Safety Film OD 5.1 is sufficient to produce a safe solar filter with excellent image sharpness.

For direct solar observation and front-mounted objective filters

AstroSolar® ClearWhite Safety Film OD 5.1 can be used for direct solar observation with the naked eye when handled correctly. This requires that the film is undamaged and used in a suitable, light-tight, and securely mounted holder.

For telescopes, binoculars, spotting scopes, and camera lenses, the film must only be used as a front-mounted objective filter. The filter must be positioned in front of the optical entrance aperture, securely cover the entire opening, and be protected against slipping, loosening, or being lifted by wind.

Visual and photographic use

The AstroSolar® ClearWhite Safety Film OD 5.1 is equally suitable for photography and visual observation. With the focal ratios of typical telescopes and camera lenses, exposure times are short enough to capture sharp images of the sun in single exposures or to perform lucky imaging. This is perfect for observing and photographing the sun under normal conditions as well as during the partial phases of solar eclipses.

You also do not need to worry when looking through a camera viewfinder, as this can be done safely when the filter is correctly installed in front of the optical system.

Construction of custom solar filters

High-quality solar filters for telescopes, binoculars, spotting scopes, and camera lenses can be made from AstroSolar® ClearWhite Safety Film OD 5.1 in just a few simple steps.

Detailed assembly instructions and safety information are included with every sheet of film. They are also available for download on this website. Stress-free mounting is essential: the film must not be stretched tight or pulled under tension. It should be mounted wrinkle-free, but without mechanical stress, in order to preserve its high optical quality. The film may sit slightly wavy or somewhat loose in the holder without negatively affecting optical performance.

Inspect both the film and the holder before each use. Do not use the film if it shows tears, holes, creases, major scratches, delamination, loose areas, or extensive wipe or abrasion marks. Damaged film must not be repaired and must be replaced immediately.

Safety instructions for solar observation

Never look directly at the sun without a suitable and undamaged solar filter. Ordinary sunglasses, emergency blankets, CDs, photographic neutral density filters, or other untested materials are not suitable for visual solar observation, as they may transmit dangerous portions of invisible radiation (UV and IR) that are not directly visible but can still cause permanent eye damage.

A safe solar filter is also required during a partial or annular solar eclipse. Only during the brief phase of complete totality in a total solar eclipse - when the sun´s photosphere is entirely covered by the moon - may the solar corona be observed without a filter. As soon as any part of the solar disk becomes visible again, an appropriate solar filter must be used at all times.

Children may only use solar filters under adult supervision. Never leave solar filters, eclipse glasses, handheld viewers, solar telescopes, binoculars, or cameras unattended.

Images from a comparative test

Interferometrical Test


Reference
Ideal picture - Strehl 1.01
(only theoretical)




Baader AstroSolar
close to the optimum -
like a good objective




Mylar Solar foil
irregularities are obvious. This would be
neither a good filter nor a good objective



Star test


Reference
Airy disc - 99.9% Strehl
(only theoretical)




Baader AstroSolar
94,1% inside the Airy disc
Comparable with a very good objective




simple mylar solar filter
57,2% inside the Airy disc
not diffraction limited any more

Safety informations: PDF Download