Baader photographic AstroSolar photo solar filter foil OD 3.8, 20x30 cm

• AstroSolar Solar Filter Film (photographic) 20x30cm, telescope quality, neutral density OD = 3.8
  For digital solar photography at highest magnifications and short exposure times. Not suitable for visual observation.
  This film is interferometrically tested to 94-96% definition brightness – making it as good as a Carl Zeiss APQ lens.
  Important note: Photographic film with an optical density of 3.8 must not be used for visual observation. Photographic film is also used exclusively for photographing the sun at highest magnifications – in conjunction with a suitable projection eyepiece.
  
  Important note: Not suitable for visual observation!

Composition: Representation of visible solar phenomena © M. Weigand
Baader AstroSolar® Photo Solar Filter Film – OD 3.8
For digital solar photography at the highest magnifications – in a handy A4 format, approx. 20x29 cm


This film is only suitable for experienced astrophotographers. Baader AstroSolar® Photo Film OD 3.8 is not designed as protection for visual observation. Photo film is also not necessary for photographing the sun with a camera lens – that would be far too bright at the low magnification of a telephoto lens.

All Baader AstroSolar® solar filter films are interferometrically tested to 94-96% definition brightness – making them as good as the best astronomical optics, e.g., an APQ lens from Carl Zeiss (Pleiger test report can be found online at Baader Planetarium). Unfortunately, we ourselves find it difficult to detect any difference in quality compared to our much more expensive flat lenses. This is only possible at very high magnifications above 250x. For higher magnifications, we recommend our Baader Cool-Ceramic Safety Herschel Prism. Our film is demonstrably sharper than all competing products known to us, especially including US glass filters.

Most importantly, our film shows the sun in its natural color – neutral white! Other films only show a blurred, bluish, or orange image of the sun.

The AstroSolar® Safety film is made from a special, streak- and bubble-free film and, with a thickness of only 0.010 mm, achieves the optical quality of plane-parallel glass filters. The carrier material is not Mylar! This film was originally developed for nuclear and elementary particle research laboratories.

Unlike glass filters, AstroSolar® is almost completely free of pinholes (holes in the reflective layer) because it is coated on both sides. The coating is subject to constant quality control. The quality of the solar image and the safety for the eyes are incomparably better than when using so-called rescue foils or similar aids that require multiple layers.

The development of the AstroSolar® foil was only possible due to the tremendous demand during the 1999 solar eclipse. Dozens of kilometers of foil were destroyed during experiments in order to develop the manufacturing process for a completely molecularly uniform foil on our behalf.

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Notes and specifications for Baader AstroSolar® PHOTO Film OD = 3.8

This film is only suitable for experienced astrophotographers. Baader AstroSolar® Photo Film OD 3.8 is not designed to protect the sun during visual observation. Photo film is also not necessary for photographing the sun with a camera lens – this would be far too bright due to the low magnification of a telephoto lens.

AstroSolar® Photo Film is used with astronomical telescopes – and only in conjunction with fast digital video cameras – to virtually freeze the finest details of the sun's surface despite the highest photographic magnifications thanks to ultra-short exposure times (using the so-called Lucky Imaging process). This is the only way to eliminate the image-destroying air turbulence of the Earth's atmosphere during solar photography. In our opinion, the image results achievable with this combination of devices are quite impressive – see also the photo gallery and our customer reviews at www.AstroSolar.com.

Do not use the AstroSolar® Photo Film 3.8 unless you are certain that you have sufficient experience in solar videography to safely handle the risks associated with using such high image brightness.

Unfortunately, the AstroSolar® Photo Film OD 3.8 is not intended for visual observation of the sun under any circumstances – even with additional attenuating lenses, because such combinations of different filters have not been tested for eye safety by a licensed testing center.

AstroSolar® Photo Film 3.8 consists of the same optically treated substrate with diffraction-limited properties as AstroSolar® Safety Film with an optical density of 5.0. However, the density of the metal layers on both sides of photo film with an OD of 3.8 is precisely controlled to create an optical density that still ensures a minimum of eye safety (in case one exposes one's eye to the intense radiance of the focused sunlight for a fraction of a second when adjusting the sun). Nevertheless, every care must be taken to avoid this.

Of course, combinations of AstroSolar® Photo Film with additional neutral density filters or other dielectric filters are available, which allow the sun to be viewed visually with sufficient attenuation – i.e., over a spectral bandwidth safe for the human eye – with very interesting results and without excessive brightness. However, any such filter combination would have to be officially tested to be recognized as an approved visual observation aid. However, given the multitude of light-attenuating filters available from a wide variety of manufacturers, such approvals are unrealistic because they are too diverse and too expensive. In any case, we must leave this discussion to the experts, with the clear statement that we – as manufacturers – cannot authorize any use of AstroSolar® Photo Film other than that described above.

In recent years, many experienced astrophotographers have requested an even more translucent version of AstroSolar® Photo Film in order to achieve even shorter exposure times. Unfortunately, no one can offer such a product in good conscience these days. Twenty years ago, Carl Zeiss was still able to produce single-sided coated glass filters (with coating holes) with an optical density of 3.5 and sell them for photographic use with emulsion films without any corresponding hazard warning. The most important warning was: "Small holes in the coating of solar filters are unavoidable. If these are perceived as disturbing, cover them with a fine brush and black paint." In our opinion, current product liability regulations no longer permit such bright and one-sided coated sun filters.
 

Build your own solar filter for your camera, binocular, telephoto lens, or telescope

In just a few steps, you can build a solar filter for digital solar photography using Baader AstroSolar® Photo Film 3.8 – at an incredible price-performance ratio.

You will need Baader AstroSolar® Photo Film 3.8, two sheets of sturdy white cardboard, scissors, a compass, Kleenex tissues, double-sided tape, and glue.

Detailed assembly instructions are included with every AstroSolar® film. You can also find the instructions and a wealth of other information on our website www.astrosolar.com

 

Never look at the sun with the naked eye without a sufficient filter - danger!

Only during the few seconds and minutes of a total solar eclipse (when the moon completely covers the sun) can the solar corona be safely observed with the naked eye (see photo below). The entire, hours-long spectacle – as the moon moves in front of the sun and then leaves it again – may only be viewed with safe eye protection – the Baader AstroSolar® Safety Film 5.0 in combination with additional optics (not to be confused with the AstroSolar PHOTO film offered here). For solar observation with the naked eye, please use our certified AstroSolar® Silver/Gold Solar Viewers.

You must also protect yourself for all other types of solar observation, e.g., during a partial solar eclipse, an annular solar eclipse, or your daily quick check of the sun (in search of large sunspots). Even when the sun is 99% covered by the moon, the remaining photospheric crescent is still dazzlingly bright and can only be safely observed with appropriate eye protection.

Never attempt to observe the sun with the naked eye, with regular sunglasses, or with unsuitable filters! Any negligence in choosing the right sun protection can lead to permanent eye damage or blindness.

Images obtained with AstroSolar® film: The left and middle images were obtained with AstroSolar® Photo Film (OD 3.8), the composition of the partial solar eclipse on the right with AstroSolar® Safety Film (OD 5.0). Images from left to right: © Christian Viladrich, © Alessandro Bianconi, © Martin Rietze

MANUFACTURER Baader Planetarium
ITEM NUMBER (#) 2459278
EAN CODE 4047825034595
NET WEIGHT (KG) 0.03
ASTROSOLAR FILM AstroSolar Photo Film
OPTICAL DENSITY 3.8
INNER DIAMETER / CLEAR APERTURE (MM) approx. 20 x 29 cm
SUNLIGHT WAVELENGTH White light (integral light)