Baader Solar Film

[simon84]

Hi all,

I've been looking at doing some solar viewing, for my little ones aswell as staying up late these days isnt possible for them.

I've been reading up on the Baader Solar Film and it seems to have a good write up but has anyone had any experience using it.

Am I right in saying that I just have to make an adapter to fit on the end of my 80mm frac and pop it on there?

What can I exect to see with it and is it as safe as they claim. I'd probably just go for it if it was just me using it but as my children will be viewing aswell I just want to be doubly safe.

[Merlin66]

I think 90% of all the white light solar observers use the Baader solar film.

If securely attached to the aperture of the scope ( also remember the finder!) it's 100% safe.

You'll be able to see sunspots and bright faculae as well as surface granulation....

Ken

[Andrew*]

Baader film gives a great white light view, allowing you to see sunspots and surface granulation.

The film itself is perfectly safe, but it's how it's used that determines the overall safety. The filter you make should fit securely and not be prone to falling off. Also, it should be checked for pinpricks prior to use.

A good safety check is to point it at blank sky before moving over to the sun. If the filter is in good condition, the view should be black.

Andrew

[simon84]

Excellent advice, thanks chaps. I will deffinitley be getting some now.

Tell me, how do I got about observing prominences and solar flares, I think thats right, with a non-solar scope?

[Andrew*]

Unfortunately that's not possible. For that you need a specialised solar scope, which precisely passes a very narrow wavelength. They cost upwards of £500.

Regular scopes can be modified to do this, but again, this costs over £500...

Andrew

[simon84]

Ahwell, thanks for the information though. I'll see how we go with the Baader film and then maybe one day look at a solar scope.

[brianb]

With children around can I suggest you use a dew cap over the film filter? Kiddies seem to have an irresistable desire to handle shiny things, apart from the risk of tearing it's impossible to clean sticky finger marks off the stuff. And never leave the scope unattended just in case someone points it at the sun in an unsafe state.

[Peter Drew]

When you make your Solar filter, remember that the material should be in a "relaxed" state, dont't try and fit it like a drum skin. The wrinkles have no harmful effect on the image.

[simon84]

Thanks again for the advice. Brian it sounds like you've met my little ones!

[Pete Presland]

i have been thinking about doing exactly the same with summer around the corner.

this sort of filter turns up on astro boot occasionally - Astro Engineering SolVue solar filter featuring specially adapted Mylar film,is it as good as the baader filters.

[GuillermoBarrancos]

Unfortunately that's not possible. For that you need a specialised solar scope, which precisely passes a very narrow wavelength. They cost upwards of £500.

Regular scopes can be modified to do this, but again, this costs over £500...

Andrew

I thought the additional 1.25" CaK EP Filter from Baader (that shows the sun in blue'ish) would allow you to see Solar Flares?

At least that is how they advertise this CaK EP filter.

It's not cheap tho. Think around 240 euros/pounds/dollars average for that filter.

And then ofcourse you got the Ha filter setup. But that goes way way beyond 500 pounds mark and almost ends up in the second mortgage catagory.

[brianb]

I thought the additional 1.25" CaK EP Filter from Baader (that shows the sun in blue'ish) would allow you to see Solar Flares?

This is a wideband filter & gives a view intermediate between narrowband CaK filters (Coronado, Lunt) & "white light". It requires to be used with a special solar film filter with higher transmission than usual.

CaK is only just visible, to most people - I see nothing at all, many people see only a dim purple glow which won't focus (a defect of the eye/brain combination, not an optical issue).

However, yes, I've imaged flares in CaK and exceptionally strong ones can even be seen in white light, the history goes back to the 1850s.

[GuillermoBarrancos]

This is a wideband filter & gives a view intermediate between narrowband CaK filters (Coronado, Lunt) & "white light". It requires to be used with a special solar film filter with higher transmission than usual.

CaK is only just visible, to most people - I see nothing at all, many people see only a dim purple glow which won't focus (a defect of the eye/brain combination, not an optical issue).

However, yes, I've imaged flares in CaK and exceptionally strong ones can even be seen in white light, the history goes back to the 1850s.

So when you use the CaK 1.25" filter on the EP end.

You then use the Photography grade Baader Solarfilm on the tube end? Wich passes through more light.

[brianb]

So when you use the CaK 1.25" filter on the EP end.

You then use the Photography grade Baader Solarfilm on the tube end? Wich passes through more light.

Yes. With no filter on the objective the heat will "pop" the filter.

IMHO a Lunt CaK diagonal is a better bet. More expensive, sure, but works better & is more or less idiot proof (though note that it is rated only for refractors up to 4" aperture!)

[GuillermoBarrancos]

Yes. With no filter on the objective the heat will "pop" the filter.

IMHO a Lunt CaK diagonal is a better bet. More expensive, sure, but works better & is more or less idiot proof (though note that it is rated only for refractors up to 4" aperture!)

No you do not understand.

You have 2 grades of Baader Solar filter sheets.

One is for visual use. The other is for photography use (lets through more light).

[brianb]

you do not understand.

Sorry, i DO understand ... the issue here is that the "photo" film is not safe to use visually on its own, and neither is the eyepiece end filter; but the "photo" film looks exactly the same as the "visual" film, so a mistake is IMO likely. Make a mistake & you risk loss of eyesight. Not worth the risk IMHO especially since the reported performance of the Baader photo film / CaK filter is not good for imaging, and most people find CaK impossible visually (if you've had your natural eye lenses replaced by glass in an operation to repair cataracts you may be one of the very few who can observe visually in the CaK band).

The Lunt CaK diagonal requires no objective end filter. The objective facing end of the device contains its own filter which reflects the vast majority of the heat & light straight back up the tube & out of the objective. However the concentration is still an issue, which is why the device is limited to 4" aperture on safely grounds.

[GuillermoBarrancos]

Sorry, i DO understand ... the issue here is that the "photo" film is not safe to use visually on its own, and neither is the eyepiece end filter; but the "photo" film looks exactly the same as the "visual" film, so a mistake is IMO likely. Make a mistake & you risk loss of eyesight. Not worth the risk IMHO especially since the reported performance of the Baader photo film / CaK filter is not good for imaging, and most people find CaK impossible visually (if you've had your natural eye lenses replaced by glass in an operation to repair cataracts you may be one of the very few who can observe visually in the CaK band).

The Lunt CaK diagonal requires no objective end filter. The objective facing end of the device contains its own filter which reflects the vast majority of the heat & light straight back up the tube & out of the objective. However the concentration is still an issue, which is why the device is limited to 4" aperture on safely grounds.

I guess we were just misinterpreting eachother.

I had a look at those CaK diagonals. And they are a hell lot more expensive yes. 900 dollars for the cheapest one.

Plus they are not usable on my scope either.