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Message: <blockquote data-quote="Binastro" data-source="post: 3185169" data-attributes="member: 111403">.The only problem with a 97% eclipse is that it is definitely not a total eclipse.I saw something similar in 1999, but not the total eclipse.It was interesting in that the light became strange and shadows maybe sharper.However, the percentage of clear days in the Shetland Islands may be better than the Faroe Islands or Spitsbergen. The last two are where the Eclipse chasers are travelling. Or they are on ships travelling along the path of totality.I want to clarify something about welders glasses.I have just seen it claimed that welders goggles are unsafe because of ultraviolet leakage. However, I think that the main point of welders glasses is to prevent eye damage, particularly from the ultraviolet.It is true that the lighter shades are dangerous when it comes to viewing the Sun.However, I just looked at a Royal astronomical Society diagram and graph showing the transmittance of a welders glass 14, and they suggest that it is safe for direct viewing of the Sun. This is a view held by several astronomical sources.The reason why I suggested that a welders glass 13 might be reasonable is that, in the past I have found it difficult to buy welders glasses shade 14 in England. I had to pre-order five glasses and this is too late for the eclipse.But welders glasses shade 13 were often in stock, although they might be difficult to find if there has been a rush on these items because of the Eclipse.I would much prefer somebody uses a welders glass 13 larger size tilted, when it is probably about shade 13.5, than somebody risk looking at the Sun with no protection at all.Also for Britain the elevation of the Sun at the time of the eclipse is around 25° or maybe 30° at the end.Generally, I found that at this elevation a tilted welders glass 13 larger size seems to give adequate protection and a good image.But I do not use the welders glass 13, even tilted, when the sun's elevation is above 45°. This is especially if the sky is transparent and the sun bright. Then I use a welders glass 14.But often in England at lower Sun elevation a welders glass 14 is a bit dark if there is a small amount of cloud, such as Cirrus cloud.In any event, the total exposure time I use in any one day is one minute. And I rarely exceed 10 seconds maximum at one time.If you do not have a welders glass 14 and only have a welders glass 13, preferably the larger size, if the Sun seems a bit bright it should be tilted. And I would keep to a maximum exposure time of 5 to 10 seconds and limit carefully the total exposure time.For countries where the sun exceeds 60° elevation I would always use a welders glass 14 or perhaps even shade 15 if they are available. This is particularly if the sky is very transparent or one is viewing from a high mountain or anywhere that is high above sea level. Here the atmosphere gives lesss protection.The free Eclipse glasses given with the Sky at night magazine seem to be shade 14.For the eclipse, the safest procedure is to project an image as discussed in the above thread.This eclipse event can be safe if you stick to the safety tips listed above.The Royal Astronomical Society also has good information on their website.For those who don't wish to watch the eclipse that is fine and safe. But for those who do wish to follow it please take care. And for heaven's sake don't use any unsafe homebrewed or home-made dark filters. Stick to the advice that has been built up over the last 50 years to try and make eclipses safer.</blockquote>

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