Quote:
Originally Posted by gregbradley
Unless there were some graphs and images that prove otherwise it seems a doublet is risky. I do recall Roland Christen saying it was possible to make an APO doublet but I don't see any AP scopes using that formula.
Thanks for the advice. Also a bit suspect about Lanthanum and whether its entirely non radioactive or is there a tiny portion that is.
Greg.
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If you are concerned about lanthanum in glass, you'd better throw away your TV, fluorescent tubes, camera lenses...
"Lanthanum is one of the rare chemicals, that can be found in houses in equipment such as colour televisions, fluorescent lamps, energy-saving lamps and glasses. All rare chemicals have comparable properties. La2O2 is used to make special optical glasses (infrared adsorbing glass, camera and telescope lenses). If added in small amounts it improves the malleability and resistence of steel. Lanthanum is used as the core material in carbon arc electrodes. Lanthanum salts are included in the zeolite catalysts used in petroleum refining because they stabilize the zeolite at high temperatures.
Health effects of lanthanum
Lanthanum is mostly dangerous in the working environment, due to the fact that damps and gasses can be inhaled with air. This can cause lung embolisms, especially during long-term exposure. Lanthanum can also cause cancer with humans, as it enlarges the chances of lung cancer when it is inhaled. Finally, it can be a threat to the liver when it accumulates in the human body."
Read more:
https://www.lenntech.com/periodic/el...#ixzz5KL6YUg51
https://www.sciencedirect.com/topics...nthanum-oxides
Of course, everything has a risk, and it seems at one point or another, EVERYTHING has been labelled carcinogenic (anyone else remember in the 80's when they tried telling us apples were?), so make your own informed decision. Seems Vixen is not concerned, nor many other manufacturers.