[Tfug] Yet another optics question

[johngalt1]

With my totally unqualified opinion, I would go with what 
the guy in the climate change business, (ostensibly) said...

Just go with the 1460X six volt lamp as B&L designed. It's 
really common and easy to get by mail order. Its color 
characteristics are probably consistent. Kind of looks like 
an automotive lamp base with a flange...

Having said that, the lens assembly is probably like that of 
a photo enlarger condenser. As I understand it, it takes a 
point source and gives light focused at infinity. Good as an 
illuminator.

If you wanted to play around have money to blow you could 
get a cheap high power LED emitter from a place like Deal 
Extreme. Place it at the focus where the lamp filament is. 
Give it an appropriate heat sink. The microscope power 
supply might work too.

Have fun!


----- Original Message ----- 
From: "Bexley Hall" <bexley401 at yahoo.com>
To: "Tucson Free Unix Group" <tfug at tfug.org>
Sent: Monday, December 21, 2009 5:04 PM
Subject: [Tfug] Yet another optics question


> The bulb in the light source for my stereomicroscope is 
> made
> of unobtanium-247 (not quite as hard to come by as u-248 
> but
> damn close!).  And, it throws off a *lot* of heat -- 20W!
>
> I am tempted to replace the light source with a set of
> white LEDs.  This frees me from the worry of having to
> worry about finding another lamp N years hence as well
> as cutting down on power consumption, etc.
>
> But, the light source has some optics in it to produce a
> focused light:
>
> http://www.science-info.net/docs/b-l/BL_Nicholas_Illuminator.pdf
>
> The "lens" (lens assembly?) appears to be a pair of 
> plano-convex
> lenses with a "light pipe" between them (I think this is 
> just to
> compensate for the mechanical design of its mount -- but 
> it
> may have optical consequences too?).  I.e. the entire lens
> assembly is probably 2 inches thick.
>
> My question:  do I need to situate the LEDs at the same 
> position
> of the filament in the original bulb?  If so, that would 
> suggest
> I need to use a single ultrabright LED as trying to locate 
> multiple
> LEDs in the same small region would be problematic.
>
> Or, should I just buy a few bulbs (they are about $10 
> each), hope
> they don't fail prematurely, and just live with all the 
> heat
> thrown off, etc.?
>
>
>
>
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