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Welding glass as a solar filter

Mr TamiyaCowboy

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Mr TamiyaCowboy

Mr TamiyaCowboy

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i wanted to ask this before i do something stupid and damage my eyes.

i have been reading, and looking at websites, and have noticed people using what looks to be welders filtering glass to view the sun and sunspots.

i also spotted the same type thing being used on the Horizon solar storm TV program this week to. i wanted to know if this glass filter is safe to use on my telescopes. fitting the filtering glass to my end caps on the scope tube.

now if this glass can be used i wondered what is the best to go for. i have found a source for Shade 11 welders glass but did not what to purchase and use this filter, before i ask the pro's on the site and/or damage my already failing eyesight.

any help/advice will be very well used and taken onboard

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kharga

kharga

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I would not use welding glass as it is not necessarily filtering out the correct wavelengths. You would be much safer using something like Baader astrofilm.

"Baader Planetarium is proud to present a new safety film for solar observation. It is made for the construction of high-quality objective-filters for observing the sun with telescopes, binoculars, camera or video-lenses. This foil is CE-tested and reduces the intensity of sunlight by 99.999% (neutral density 5.0)."

See http://www.baader-planetarium.com/sofifolie/as_40jahr_en.jpg

Approx price £19.00 for an A4 sheet - not cheap but you only have one pair of eyes!

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Mr TamiyaCowboy

Mr TamiyaCowboy

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so it is safe to say the horizons program was/is putting bad ideas into peoples heads.

i have seen solar filters with the badder film in but £45 for a filter to fit my scope is very high just for film and a holder. and an A4 sheet will barely fit the 114 scope end cap (full aperture ) leaving me less than an inch to play either side to make a decent and safe holder.

http://www.bbc.co.uk/iplayer/episode/b01d99vb/Horizon_20112012_Solar_Storms_The_Threat_to_Planet_Earth/ link to the horizons programe in question.

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Stephen

Stephen

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so it is safe to say the horizons program was/is putting bad ideas into peoples heads.

i have seen solar filters with the badder film in but £45 for a filter to fit my scope is very high just for film and a holder. and an A4 sheet will barely fit the 114 scope end cap (full aperture ) leaving me less than an inch to play either side to make a decent and safe holder.

Only if you make the assumption it was welding glass used on the program.

I'm confused by which scopes you are referring to, I made a full aperture (OK so I lost maybe 10mm each side) for an 8" from one sheet?

£15 + £5 bits to assemble it. I say once again, it's one of the cheapest accessories you will ever purchase :)

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peeceeTal2M

peeceeTal2M

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I think that shade 14 welders glass would be the minimum, but they might not filter out all damaging wavelengths put out by the sun, also its not optically flat so will distort your view. To be on safe side i'd go for the baader film... £20 to prevent eye damage has got to be worth it!

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Anweniel

Anweniel

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Isnt A4 something like 200mm x 300mm? with a 114mm reflector that leaves at least 43mm on the smallest 2 edges to go round the end of the tube, I cant imagine the tubing to be so big as to leave nothing spare in in 43mm?

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David Smith

David Smith

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For sunspot viewing why not project suns image onto a sheet of white card, i used to get great images this way with my Tal

I observed the sun for many years in this way with my old Tasco 60mm frac. Works really well. Use an eyepiece your not so keen on though just in case you fry the coatings.

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182570

182570

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For sunspot viewing why not project suns image onto a sheet of white card, i used to get great images this way with my Tal

For some reason this method seems to be less popular these days,costs nothing and is 100% safe.:)

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Grunthos

Grunthos

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i wanted to ask this before i do something stupid and damage my eyes.

Let me be blunt and straight to the point.

Do not use welders glass (or any variations) with a telescope or binocular. Don't even think about it. The magnifying power of the instrument will ensure you damage your eye(s) in very short order. (welders glass of grade 14 and above may be used to look at the Sun directly but not magnified).

Invest in a decent solar filter or make your own from solar film (as alluded to on this thread). £15 to £45 is not a high price to retain your eyesight is it? (I'd take out a second or third mortgage to keep my eyesight!).

Solar filters/film should always be placed on the Objective lens (i.e the front end) of the astronomical instrument.

The

is also a well tried and trusted system.

You've heard it before, I'll say it again. The Sun can permanently blind you.

Here endeth the lesson...

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Cath

Cath

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For some reason this method seems to be less popular these days,costs nothing and is 100% safe.:)

Their is a thread on here today (can't find it now) where someone tried this only to destroy their focuser and other parts of there scope. That's why it's less popular these days.

To be honest, if £15 or so is too expensive to protect your eyes (and probably much more behind them) then I'd say find a new hobby.

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peeceeTal2M

peeceeTal2M

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I observed the sun for many years in this way with my old Tasco 60mm frac. Works really well. Use an eyepiece your not so keen on though just in case you fry the coatings.

Yes, i allways used an old eyepiece, and blanked off most of the open end, its amazing how hot the lens can get when sunspot projecting.

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Bluey

Bluey

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I have just made a filter with solar film for a 10" dob, just used black card with a 4" offset aperture cut in it, I managed to get a quick look at the sun earlier and all looked fine, and I'm not blind.

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jonathan

jonathan

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It's like sunglasses - if you buy a cheap pair they are probably not fully UV protected so will not protect your eyes in the slightest, just make things look a bit dimmer.

Solar filters (and solar telescopes) are like super-duper sunglasses, built for the job.

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Mr TamiyaCowboy

Mr TamiyaCowboy

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am getting some badder film but would like to know out of my two scopes what will be the best one to use.

SW heritage 76 table dob (300mm)

SW 114 catadioptric dob (1000mm has a lens fitted inside the focuser)

out of the two above what is the best one i should make a solar mask for. and should i go for full aperture or a small cutout.

i was thinking smaller hole is less film used ? or should i use all the film sheet for one scope.

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