EBBCO sextant - filters have UV removing properties?

oldvarnish said:
And andygc has 'explained it very nicely' once again. Good night
Click to expand...

Really? Do you think so? Really?

He should have read the thread in its entirety before writing.

The ebbco sextant has PLASTIC filters, not GLASS so he did not "explain it very nicely once again".

I wish his profile was more complete than born 1st Jan 2014. What is he basing his comments upon. What are his qualifications?

We know we have chemists, gp's, lawyers etc on here, but andygc has not qualified any of his statements.

I am not going any further, I suspect a troll.

Out.
 
Sailingsaves said:
I am not going any further, I suspect a troll.
Click to expand...
I struggle to understand your reason for rudeness.

If you had any knowledge of this subject you would be aware that UV radiation is attenuated by passing through most transparent and translucent media. That includes clouds, glass sextant lenses, plastic sextant filters, and your cheap sunglasses. That attenuation is a consequence of the properties of such media - they absorb UV. The makers of cheap sunglasses don't need to put any effort into making them absorb some UV - the plastics that lenses are made of do that anyway. Incident light in a sextant passes through lenses, made of glass, and filters, made of glass or plastic.

As I wrote before, you can choose to believe what you like. If you want to believe that your plastic sextant is a hazard to your ocular health, you are perfectly free to do so. I posted because there were obvious misunderstandings in the thread which needed correction. I've explained the realities of UV exposure and have nothing more to add. I fail to understand why you bothered asking the question if you aren't willing to accept a factual answer which happens to contradict your misguided beliefs.
 
For all I know, you know nothing as you have not given any evidence to back up your statements or told us you are an optician or physicist (as I used to be).

You also failed to address some points I made.

Other well respected forumites with known qualifications (AntarcticPilot) have made sensible, logical statements.

Yours just says (with no evidence) after having failed to even realise we were talking about PLASTIC filters (do you read threads before replying) "that all is ok, don't worry, trust me...I'm a ... well... a ...forumite with an opinion."

Quote:"If you had any knowledge of this subject you would be aware that UV radiation is attenuated by passing through most transparent and translucent media."
So we don't need any suncream because UV is attenuated to lovely harmless degrees. My oncologist and the plastic surgeon cutting out mole after mole would take issue with you.

And here I am biting at your hook again when I think you are just a troll (something you have an interest in apparently ref one of the few threads started by you):

http://www.ybw.com/forums/showthread.php?255266-Troll-of-the-Year-Prize-2010&highlight=

andygc said:
I struggle to understand your reason for rudeness.

If you had any knowledge of this subject you would be aware that UV radiation is attenuated by passing through most transparent and translucent media. That includes clouds, glass sextant lenses, plastic sextant filters, and your cheap sunglasses. That attenuation is a consequence of the properties of such media - they absorb UV. The makers of cheap sunglasses don't need to put any effort into making them absorb some UV - the plastics that lenses are made of do that anyway. Incident light in a sextant passes through lenses, made of glass, and filters, made of glass or plastic.

As I wrote before, you can choose to believe what you like. If you want to believe that your plastic sextant is a hazard to your ocular health, you are perfectly free to do so. I posted because there were obvious misunderstandings in the thread which needed correction. I've explained the realities of UV exposure and have nothing more to add. I fail to understand why you bothered asking the question if you aren't willing to accept a factual answer which happens to contradict your misguided beliefs.
Click to expand...
 
Last edited:
"but I am forcing myself NOT to go that route" Geeez! I know the feeling!

I bought an Ebbco on eBay for $15 which had seen better days. The mirror had de-silvered to a large degree but I fixed that with a bit of mirror off the local rubbish dump. But I think there may be a lens missing from the eye piece. There is a lens near my eye but nothing at the other end of the tube. Is there one in yours? The local optician said it could well be plain glass just to keep the dust out.
 
You must log in or register to reply here.

Share this page

Top