Looking for recommendation regarding glass solar flter

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Avraham
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Looking for recommendation regarding glass solar flter

Post by Avraham » Fri May 11, 2012 11:44 am

Hi

I'm looking for the absolute safest, high quality glass filter for my ETX.

Any models come to mind?


thanks,
Oded

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Re: Looking for recommendation regarding glass solar flter

Post by solarchat » Fri May 11, 2012 12:06 pm

Hey Oded, thats a tricky one. Baader solar film is the best solution for white light with an ETX but it is not the safest. The Orion Type II glass filter is the safest but not very good relative quality. Zeiss makes a glass filter but it would be about twice as much as the scope.

I think you would be far happier, and spend less money, buying a small, medium quality 80mm refractor and a Lunt Solar wedge and just using the ETX for that sissy night time stuff. :) The ETX's are great for night time but they are just not the best match for solar.
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Re: Looking for recommendation regarding glass solar flter

Post by marktownley » Fri May 11, 2012 2:01 pm

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Re: Looking for recommendation regarding glass solar flter

Post by Avraham » Fri May 11, 2012 2:37 pm

Thanks Mark

Bit since ii'm using it on the public, i need all my equipment factory new.

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Re: Looking for recommendation regarding glass solar flter

Post by trwinship » Mon Jun 18, 2012 12:25 pm

Just curious--how is the Baader film not safe on an ETX?

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Re: Looking for recommendation regarding glass solar flter

Post by Avraham » Mon Jun 18, 2012 12:33 pm

Oh,

I's not unsafe per se. But it's a more vulnerable. I must avoid those tiny scratches that suppose to come with time and so on.

This could be psychological, I admit.

But also important: The last thing I want to deal with, is inadvertently afflicting some poor kid's eye with any damage, or some ignorant parent asking me "This? THIS FLIMSY PIECE PLASTIC is what you let my kid look at the sun with?!"


All things to consider. :-)

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Re: Looking for recommendation regarding glass solar flter

Post by trwinship » Mon Jun 18, 2012 1:04 pm

OK, fair enough. But I'm also wondering why an ETX wouldn't be suitable for solar observing. Granted it isn't quite the same, but I've used a Celestron C90 Astro (with both glass and film filters) for solar observing public programs with great success for more than 25 years. Again, not arguing just wondering what the problems are. Now, nowadays I mostly use a Celestron C6R with a Baader wedge, which is better for certain but the C90 really isn't bad.

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Re: Looking for recommendation regarding glass solar flter

Post by Avraham » Mon Jun 18, 2012 1:07 pm

Did I say the ETX is not suitable? :-)

On the contrary. I'm a big fan due to it's optics, versatility, and durability. Fits in the bag and all.

Here, they just let out a "new" one Nothing in the optics was changed, just some plastics and engines.

I use it daily observing the sun.

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Re: Looking for recommendation regarding glass solar flter

Post by Merlin66 » Mon Jun 18, 2012 4:35 pm

I believe the Baader Solar film is every bit as robust and safe as any of the glass filters.
Certainly gives great performance.
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Re: Looking for recommendation regarding glass solar flter

Post by trwinship » Mon Jun 18, 2012 9:18 pm

Well, to get back to the original topic, of the suppliers of glass filters the only one I would specifically avoid is Orion. In using one of their filters very recently I saw no unexpected optical problems (the image was fine at low and medium powers) but the filter cell used was just plain cheap--very thin metal that deformed readily under pressure from the setscrews or from just pushing the filter on the end of the scope. The setscrew retainers in the cells were very loose and would be easily lost. I don't know what the current situation with Thousand Oaks is but in the past I found their white light filters, while not up to Zeiss optical quality, were built well for the price--about $85 for the ETX I believe. And again, at low to medium power they worked fine. If you prefer a glass filter, go for it! You may well wish to upgrade to a refractor in the future (I did) but for public outreach at present you'll do fine.

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Re: Looking for recommendation regarding glass solar flter

Post by brianb11213 » Mon Jun 18, 2012 10:22 pm

I've seen TO & Orion glass filters, every one has been optically substandard, some have had quite serious issues with obvious double images. Like looking through ordinary window glass, which is what I suspect they're made from.

In my experience Baader solar film is actually tougher than glass - at least it won't shatter when dropped. You need to protect the optical surfaces anyway. The only downer is that the stuff is hard to impossible to clean, but then it's cheap enough to replace occasionally. TO & Seymour solar films are if anything thicker & tougher, not as good optically for that reason, and I find the rather dense orange/yellow colour annoying especially if trying to image through it. You need a "natural" bluish white presentation to accept a full range of filters, the exceelent Baader solar continuum filter in particular.

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