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Using Solar Filter Film

onesmallstep

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onesmallstep

onesmallstep

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Hi

At this morning's Transit of Venus event an amateur astronomer turned up at our location with his scope, a new purchase. He had heard about my astro group and the ToV on local radio and had always wanted to get into the hobby. So far, so good! He had bought his telescope with him and wanted help setting up when I noticed that his solar observing kit consisted of the unfiltered scope and a pair of welders goggles that he was going to wear when looking through the eyepiece. Luckily (in this case) he didn't get to try out his system. I explained about solar filters including Baader filter film but I don't think he really understood what I was trying to tell him.

Can somebody please explain to me how to use Baader film so that I can pass this info onto him.

Thanks in advance.

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Digz

Digz

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Blimey, that could have really done some damage to both his eyes and scope!!!

Basically with the solar film you can either make a full aperture mask or a mask for the scope cap (if it has one). Check my blog (link in sig) I have a couple of images of what I did. The key thing is to have the solar filter on the front of the scope to prevent the scope being fried. Also make sure any finder is removed from the scope to prevent any damage from the sun passing through that un-filtered.

If you need anything else feel free to ask.

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onesmallstep

onesmallstep

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It comes with instructions, but basically you make a sandwich of it using cardboard holders and the film, and securely fit that to the front of the scope.

Thanks. I've actually read the instructions but they are in Chinglish so get a bit confusing. I did explain this to the newbie but he seemed confused, even when we showed him a similar scope that had been filtered using this film on the inside of the scope cover. If it exists I'm after an idiot's guide to using this film so that I can forward the info to him.

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onesmallstep

onesmallstep

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Blimey, that could have really done some damage to both his eyes and scope!!!

Basically with the solar film you can either make a full aperture mask or a mask for the scope cap (if it has one). Check my blog (link in sig) I have a couple of images of what I did. The key thing is to have the solar filter on the front of the scope to prevent the scope being fried. Also make sure any finder is removed from the scope to prevent any damage from the sun passing through that un-filtered.

If you need anything else feel free to ask.

Thanks, I'll check your blog and pass on any relevant info.

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smudgeball

smudgeball

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Hi

I'm still trying out my solar filter (would have been a waterproof test this morning :grin: )

One tip I picked up and well done for pointing out the removal of the finderscope Digz is to get the maximum shadow behind the scope. i.e. it's blocking the sun and casting the biggest shadow.

I use a "proper" filter from FLO and so far it's been quite interesting viewing the sun.

Just a shame about the weather today

Neil

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Digz

Digz

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Maximum shadow Neil? Do you not mean smallest?

It's a technique I use to align the scope with the sun - keep moving until you end up with a circle being cast rather than a cylinder....that way you know the scope is roughly in the right place.

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Digz

Digz

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Aye, what you said, I got a bit muddled there :laugh:

When it's in line you see a shadow of your scope.....which would be the smallest.......it was a long day at work today !

No worries :D talking of long days at work, I'm not looking forward to tomorrow.......

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sologuitarist61

sologuitarist61

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Maximum shadow Neil? Do you not mean smallest?

It's a technique I use to align the scope with the sun - keep the scope moving until you end up with a circle being cast rather than a cylinder....that way you know the scope is roughly in the right place.

I follow the smallest circle routine as well, yet still have to move the scope about quite a lot to actually find the sun. Talking of finder scopes, I tend to keep mine on the scope for solar viewing but make sure that the lens cap is firmly on to avoid heat build up. Perhaps I should make another filter for the finder scope, then I might have more luck in finding the sun in the first place!!

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Digz

Digz

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You certainly could make another filter for your finder IMO its just one more thing to fall off (the filter that is) or forget to put on......sniff, sniff, can I smell burning......:laugh:

my finder lives off my scope in a case with my guide cam so I don't have to worry about it - which is a good job!

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cantab

cantab

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Well to explain why the filter needs to be on the front of the telescope:

The telescope concentrates the Sun's light. The filter blocks 99.999 percent of the light so the Sun can be safely viewed. Do you think the filter's task will be easier if it's placed before or after the light is concentrated?

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Nova

Nova

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I made a solar filter out of Baader film for the transit and took a few pics as I put it together and came up with this

http://stargazerslounge.com/blog/788/entry-1169-diy-solar-viewing-filter-housing/

Might find it useful. Since making it I have had the chance to use it several times including the transit and it works like a charm. Normally I align using the scopes shadow as mentioned but was no good for the transit as obviously the shadow wasnt on the ground. Another option for ailgning is a solar finder such as this

http://www.astro-engineering.com/prod/astro-engineering/solar%20finder/AC618.html

Dont think it would be to hard to knock up something similar

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