Confused about white light filters

[MimasDeathStar]

Hi all, 

I've been using an Explore Scientific filter (the big black cardboard one) with my Skymax 102 for a couple of weeks. I have no problems with it but as it was so cheap I got to wondering whether there was any way I could upgrade the view. 

Having a Mak I can't use a herschel wedge but, having looked at white light filters, I'm not having much success at cutting through the blurb! Do the glass filters work better than the film ones? Are the white filters actually better than the yellow/orange ones? What difference do the different film materials make? 

Or is it all a much of a muchness and not something to spend much time worrying about? 

Many thanks and apologies for my obvious questions! 

Niall 

[johninderby]

Think the Baader solar film is the best available so would probably be a bit better than the ES film. Tried the Seymour film that gives a yellow sun but chucked  it in the bin after one use. Just rubbish compared to the Baader.

 The problem with glass filters is that they aren’t optically flat unlike the Baader film so have more distortions. An optically flat piece of glass is horrendously expensive to produce and the cheap glass used by Orion, Thousand Oaks etc isn’t optically flat. Zeiss used to make proper optically flat glass solar filters but even second hand they can go for £1,000.00 and up. 

Edited November 20, 2019 by johninderby

[Stu]

John is right. It seems one of those odd situation where actually spending less will get you a better result! The Baader Astrosolar film is quite cheap, but optically very good and better than using a more expensive glass filter which is not as high quality.

[MimasDeathStar]

wow thanks both that's fascinating. So I suppose the glass one's are aimed at the impressionable newbie's like me looking for the best experience! Am I imagining it or are there different grades of Baader film or am I imagining it?

[Stu]

13 minutes ago, MimasDeathStar said:

wow thanks both that's fascinating. So I suppose the glass one's are aimed at the impressionable newbie's like me looking for the best experience! Am I imagining it or are there different grades of Baader film or am I imagining it?

There is visual and imaging film which cut the brightness by different amounts. The visual film is ND5.0 if I recall correctly, and must be used if you intend to do visual observing. The imaging film is not to be used for visual, although you can use visual film for imaging.

https://www.firstlightoptics.com/solar-filters/baader-astrosolar-safety-film-nd-50.html

https://www.firstlightoptics.com/solar-filters/baader-astrosolar-photofilm-nd-38.html

 

[Louis D]

I used the Thousand Oaks Silver-Black eclipse glasses for the 2017 solar eclipse, and everyone agreed the image was much sharper than the view through typical Mylar eclipse glasses.  I've been using Baader solar film for almost 20 years on telescopes, and it is definitely better than the view through a 90s era glass solar filter I once owned.  However, I'll probably try the newer TO material for new home-made solar filters to see if it is any better.  Has anyone in the UK tried it out?

[Alan64]

I had gotten a Thousand Oaks solar-film filter many years ago, and for my 102mm refractor only...

The image is yellow-orange.  The Baader solar-film is said to be superior, and the image bluish-white.  In any event, that TO filter is quite dated.  I'd be reluctant to use it again.

I've had this sheet of the Baader film for a few years, but I haven't made a filter with it yet...

When making and observing with a solar-filter, observe all precautions.  Research others' experiences with the film online, thoroughly, and prior to making your own.  You cannot be too safe in that regard.

When installing the film into a home-made frame, the film must not be stretched in the least.  It must be allowed to lay onto the glue or double-sided tape, used to secure it, under its own weight.  It will have a wrinkled appearance, which is normal...

https://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html

...but the wrinkling will not affect the view in the slightest.  You don't want it doubled over itself, nor stretched taut.  A stretched film will distort the view. 

Avoid black-polymer filters and materials.

Edited November 20, 2019 by Alan64

[johninderby]

If you want a yellow sun with Baader film simply use a yellow eyepiece filter. Also gives a tiny bit more contast. 🙂

[joe aguiar]

I like the 1000 oaks  film better,  I tried the Seymour years ago and I think it gave a green image. I also had the badder back nesr 2000's and bought the big sheet 20x30 to do few different scopes. I dont find it much better compared to 1000 oaks if it is it minor it's not a big difference at all but I dont like the white colour and I dont like to use planet filters to make it orange either.

The real sun viewing in ha.

But this is me

[Alien 13]

Are there any good glass filters for camera lenses, I need a 77 mm one that fits the filter thread.... 

Alan

[Merlin66]

Interesting the TO site mentions the "CE & ISO Certified" which only applies to solar sun glasses - not for telescopes or other optical systems.

They compare with "mylar" which I think is bad marketing - The Baader solar film is definitely NOT maylar based, and Baader give details of the optical properties - something I can't find on the TO site.

For the camera lens I would make a filter from the Baader solar film to fit the lens.

 

[JamesF]

7 minutes ago, Merlin66 said:

For the camera lens I would make a filter from the Baader solar film to fit the lens.

I was thinking the same.  It might even be possible to fix the film to a step-down ring that would fit the filter thread or something like that?

James

[Merlin66]

Sounds like a plan.....

[johninderby]

1 hour ago, Alien 13 said:

Are there any good glass filters for camera lenses, I need a 77 mm one that fits the filter thread.... 

Alan

Seymour do one but can’t find it in the UK but you can order from Amazon.com and they will deliver it just like any Amazon purchase with no,customs to deal with. Not cheap though.

https://www.amazon.com/Helios-Solar-Threaded-Camera-Filter/dp/B06X6B32KB

RotherValleyOptics does the Seymour cell with the rubbish seymour film in it. Suppose you could always replace it with Badder. The film Seymour uses is ND5 not 3.8 as you would expect in a camera filter.

https://www.rothervalleyoptics.co.uk/seymour-solar-threaded-camera-solar-filter.html

Edited November 20, 2019 by johninderby