Archived posting to the Leica Users Group, 2014/02/11

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Subject: [Leica] Lanthanide glass?
From: hlritter at (Howard Ritter)
Date: Tue, 11 Feb 2014 07:34:51 -0500
References: <>

Lanthanum is mildly radioactive, but not so much so that its use in 
eyepieces for astronomical telescopes is prohibited. Several manufacturers 
advertise that their products contain lanthanum glass.


On Feb 11, 2014, at 6:51 AM, Peter Dzwig <pdzwig at> wrote:

> Guys,
> Knowing your expertise....
> What is the issue with Lanthanum in lenses. I thought its use had been
> discontinued long ago on health grounds, maybe in the 50s, although what 
> the
> details were I don't recall. Now someone else tells me otherwise.
> ...were there other compounds discontinued for similar reasons?
> Peter
> -- 
> ===========================================================
> Dr Peter Dzwig                                
> _______________________________________________
> Leica Users Group.
> See for more information

Replies: Reply from benedenia at (Marty Deveney) ([Leica] Lanthanide glass?)
In reply to: Message from pdzwig at (Peter Dzwig) ([Leica] Lanthanide glass?)