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welding window for the sun

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5 replies to this topic

#1 MartinPond

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Posted 13 August 2017 - 12:36 AM

A lot of welding filters (#12 shade, electric arc welding) were being sold at the Stellfane swap tables,

  and while they worked great directly over the eyes, on a scope (extensively taped, lid taped well) 'moon-port',

 the image came out quite blurry.  I figured out the issue:  the tempered glass has a lot of thickness and

  strain variation, so the uneven surface is a blurry 'lens' over longer distances.

And....using it right over your eyepiece would likely bake and wreck your eyepiece...

 

So.....only good for a 1X over-the-eyes view, unfortunately.


 

#2 Cajundaddy

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Posted 13 August 2017 - 12:40 AM

Yes.  It is not optical quality glass so images are less than great.  Better than nothing but not as good as a proper optical quality solar filter from Baader, Thousand Oaks, and others.


 

#3 havasman

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Posted 13 August 2017 - 01:11 AM

#14 is generally recommended. They are additive so a 9 and a 5 would work. But as you say, that would be optically poor.


 

#4 ImNewHere

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Posted 13 August 2017 - 02:54 AM

That's what I used for the Venus transit with a Quantaray 70-300 and Pentax Kx, aka my very first "astro" pics. I still have them for eclipse stuff, but my equipment has been upgraded substantially. Ohh, that reminds me, I need to dig out my normal solar filter.


 

#5 Don W

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Posted 13 August 2017 - 10:45 AM

Welder's glass is NOT recommended for over the telescope use. They are fine for purely visual use only.  Proper filters are not expensive. Get the real thing.


 

#6 Ken Sturrock

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Posted 13 August 2017 - 02:12 PM

And on that note, locked.


 


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