Solar filter options

[Joel Shepherd]

I'm thinking about getting a solar filter for my 6" Newtonian and don't have a very good idea of what to look for or consider. I know that eyepiece filters are a no-no: that's about it.

Orion sells glass filters: sort of like the idea of that since they are wrinkle-free. On the other hand, there are reports that the glass distorts the image.

There are other filters that use Baader film, but it looks delicate and wrinkly.

What do folks recommend? I'm primarily interested in visual use though if that goes well may wind up popping a camera in in place of the eyepiece.

Thanks in advance for your thoughts.

-- Joel.

[Floater]

Go for the Baader film. You can make the filter yourself from a sheet - the most economical choice - or buy one ready made.

[ronin]

You can buy one as you say, I have a glass one and I like it, it was however produced by a good astro eng company, it is metal and it screws into the scope at the objective. I was using it on June 21st at an event and it worked perfectly. Only mention this a lot as many will say avoid glass ones, whereas mine is very good indeed.

You can buy one made from Baader solar film, nice easy option. I assume that the retailer will know to sell you a visual one made from ND5 film, the ND3 is for imaging.

If I recall there is another film, Thousand Oaks (might be wrong on the name). The difference is I think the colour of the image that is produced, Baader is white/grey TO is (if right) more yellow/orange.

With the film you can make your own. Just finishing one here that I made from model making ply, about 1mm thick so bends easy and is a bit more solid. Not easy to glue, need scissor clamps. The intention is to sandwich the film between 2 pieces of clear acetate stuff -so acetate-film-acetate - that way it is protected.

Do not stretch the film in any way if you make your own.

Suppose the easy option is to buy one for the scope, quite a few US retailers sell them I believe.

All film ones are White Light, they will show sunspots on the surface but they do not show the surface granularity or plumes etc, for that you need a solar scope or something like the Quark.

[michael.h.f.wilkinson]

Baader film is the best option. The wrinkles have no discernible effect on the image

[Steve Ward]

Without question the Baader Solar Film is the best option .

Glass filters are not made from optical quality glass and are certainly not finished/polished to an 'optical' grade  ... ( this includes the AstroEngineering filters that were mentioned before , yes the holder is well made and they screw directly on the tube in place of the end cap but the glass is just common or garden float and they cannot help but detract from the view )

They are also coated on one side only and invariably develop pinholes which need 'repairing' with a Sharpie on a regular basis.

And that's without the obvious question of durability , try accidentally dropping a glass filter and see how long it lasts ... 

Baader film is double coated meaning pinholes are rarely an issue as any holes that develop on one coating need to line up with a hole on the other side to become an issue .

And despite it's 'tinfoil' appearance the film is extremely strong , cannot be torn by hand , and bounces  ... 

The polymer based films such as Thousand Oaks or Seymour should be avoided at all costs , the view through them is dreadful in comparison and they should be reserved only for cheap eclipse glasses .

[Stu]

With the film you can make your own. Just finishing one here that I made from model making ply, about 1mm thick so bends easy and is a bit more solid. Not easy to glue, need scissor clamps. The intention is to sandwich the film between 2 pieces of clear acetate stuff -so acetate-film-acetate - that way it is protected.

I wouldn't recommend sandwiching the Baader film between acetate, there is no need. I'm sure you will get better views through just the film and as already mentioned it is pretty tough.

[ollypenrice]

I agree that Baader beats glass. My glass filter develops pinholes at quite a rate. The wrinkles are not an issue. And it's so much cheaper. Dont forget to stop off your finder!

Olly

[Steve Ward]

I wouldn't recommend sandwiching the Baader film between acetate, there is no need. I'm sure you will get better views through just the film and as already mentioned it is pretty tough.

Absolutely , the film comes with a very thin 'protective film' attached (if bought in the A4 form) 

This very thin clear film kills the view if inadvertently left on so two sheets of acetate in a sandwich will render it completely useless.

The film is very robust , mine has seen nearly three years of service , two of those on a daily basis , and is as good as it was on day one .

[jimbo747]

I was just to post that, I didn't realise there was a film on it until I tried to work out why my eclipse images were rubbish. Proper face palm moment. Still, I'll get to try again in 80 years or so.

[Steve Ward]

Interferometric data for Baader film ...

http://astrosolar.com/en/information/about-astrosolar-solar-film/interferometric-protocoll/

[Joel Shepherd]

Alrighty, sounds like Baader solar film is the recommendation. 

ronin's comment leads to the next question: With a ordinary Newtonian and visual film, what can I reasonably expect to see? Sunspots and prominences?

Would I be able to get any sort of decent results with a photographic filter and CCD, or would it take a more specialized set up to make that worthwhile?

Thanks again -- Joel.

[Davey-T]

Sunspots and some surface detail, no prom's, have a look in the solar imaging section at some of todays white light images.

Dave

[Owmuchonomy]

The Baader solar film comes in two classes, one for visual and one for photography. Be sure to purchase, and use, the correct version. With such a set up you will see sunspots and maybe faculae but not prominences. For proms you need a dedicated Ha set up to collect the light only from the hydrogen alpha part of the visible spectrum.