Baader AstroSolar film safety

[astro744]

Baader AstroSolar film safety
Baader AstroSolar film safety
Hello,

I ready recently on another forum that Baader AstroSolar film (silver mylar type not black polymer type) is not safe for unaided views of the Sun, i.e as eclipse shades; the reason being it passes unsafe levels of UV. This UV is filtered if the film is used with a telescope/eyepiece because of the glass.

I found the following on the astro-physics.com website, (see "Important Note"):

"Eye Safety
AstroSolar® is essentially free of pinholes. The patented, high-density coatings are deposited on both sides. As a result, the chance of two pinholes overlapping each other is extremely low. Baader AstroSolar® safety film has been approved by the National Bureau of Standards for eye safety in Germany and is CE tested and approved. All processes connected to this product have been thoroughly tested. Coatings are inspected constantly for consistency to ensure your eye safety!
Important note: AstroSolar® 5.0 is not designed to work as an "eclipse shade" or handheld solar filter and is not suitable for naked eye solar observation.

AstroSolar® film was designed to serve as a precision optical window for telescopic and photographic solar observation without deteriorating the optical wavefront. AstroSolar film must be used in front of the optical element of an astronomical telescope, telephoto lens or binocular. For visual observation, you must view through an eyepiece. Do not make a handheld solar filter and hold it directly in front of your eyes. If AstroSolar® 5.0 is being tested for visual observation ISO-specification, all tests must be performed with a telescope and eyepiece (or other optical instrument) added into the testing apparatus."

[doppler]

I think that you will find that the ND5 film is fine for visual, there is a ND3.8 photographic version that is not suitable for visual. OK there appears to be something to the article, but it is more to do with certification. Here's a link.
http://astrosolar.com/en/information/about-astrosolar-solar-film/differences-in-astrosolar-solar-films/

[astro744]

Thanks for the link; I didn't find this one.

No its the 5.0 visual film that I was referring to not the photographic version and the 'Important Note' I referenced implied 5.0 not suitable for visual without a some sort of optic, i.e. not unaided naked eye observation.

The link you show is even clearer in this regard and certification or not I would not be using the AstroSolar 5.0 safety film for unaided visual (naked eye only). The AstroSolar Silver/Gold film appears suitable for unaided visual according to the information provided in the link you referenced.

I thought I'd post this to inform anyone using AstroSolar film to not use it unaided (naked eye) not only for the upcoming solar eclipse (overseas) but also for general observation of the Sun. i.e. don't look at the Sun through AstroSolar 5.0 safety film unaided, naked eye.

[doppler]

Telescopes intensify light making it even brighter than naked eye, so I am a bit puzzled. I think maybe this more about durability, the Baader solar film we use with our scopes is not made for rough handling.

[Merlin66]

The Baader ND5 solar film has been used successfully for many years in both naked eye and telescope applications.
Based on my twenty year experience with the Baader solar film, I personally think it is 100% safe to use for any solar viewing.
The issue seems to be related to mis-handling and possible damage.

[astro744]

The issue was discussed on another forum. It is to do with UV light which is absorbed by any glass in the path but not when used unaided. I would recommend following any advice warning against the unaided visual use of the product.

[Merlin66]

Hmm
Have you actually reviewed the transmission spectrum of the ND5 Solar film??????
It effectively provides an ND5 attenuation across all the UV and into the NIR.
I need to republish a safety document prepared back in 2009, which gives details of the standards for protection.
(The document pdf is too big to upload 670Kb, but I can supply a copy on requested. There is a copy on the Solar Chat site, in the library files area.
ICNIRP_review https://solarchatforum.com/viewtopic.php?f=7&t=2560)

[astro744]

I don't need to test anything but follow the manufacturers recommendation. See about 3-4 paragraphs down at http://astrosolar.com/en/information/safety-instruction/safety-warning-how-to-protect-your-eyes/

You have to use the silver/gold version for unaided visual views as the standard 5.0 visual version is only for use other than naked eye.

[Merlin66]

http://www.threehillsobservatory.co.uk/astro/spectra_23.htm
https://www.rasc.ca/tov/safety


This makes interesting reading....

[Kunama]

No matter what experience and anecdotal evidence is given here, seems that the fact is that the manufacturer states it should not be used for direct visual, to advise otherwise seems unwise.

[doppler]

Apparently the standard has been updated and the old solar film doesn't pass, it's not far off spec though but rules are rules.
ISO 12312-2:2015 (http://www.iso.org/iso/catalogue_detail.htm?csnumber=59289 ) looks like you have to buy a copy here.

This is a brand-new worldwide standard, introduced in June 2015, which supersedes all previous standards, and pertains specifically to filter material intended for eye protection during direct solar viewing

https://www.eclipse-chasers.com/article/SEC2014/papers/The%20New%20ISO%20Standard%20For%20 Solar%20Filters.pdf

[Steffen]

I've used the Baader ND5 film for years on my scopes, but for eclipse shades I actually prefer the black (-looking) polymer film, that used to be sold in the IIS Shop. It makes the sun look nicer :)

[Merlin66]

OK.....
The new ISO standard has changed the game.....