Re: Kings Inn viewer done

[E R Swanson <ers@xxxxxxxxxxxxxxxxxxxx>]

I violated email protocol and left all this thread attached because it's
an important dialog. I'm going to buy the material Richard cited. 

As I mentioned in an earlier post, the 40x84 surplus achromats are a drop
in fix for getting decent optics into a King's Inn. There are a lot of
these viewers out there, so those who have one might seriously want to
consider a UV filter as an upgrade. (While you're at it consider the
optics upgrade-- coated 40x84 achromats-- same as the Saturnslide-- really
spiff it up into a decent viewer. I think these came from Surplus Shack,
or possibly the AS&S Optical catalog-- it's been awhile...)

Richard, thanks for the good information!

Elliott

On Tue, 27 Apr 1999 rlrylander@xxxxxxx wrote:

> 
> 
> Alan Lewis wrote:
> 
> > E R Swanson wrote:
> > >
> > > My question, Alan supplied a little UV filter with the Saturnslides. How
> > > essential is this? Should I be concerned about the amount of UV coming off
> > > a fluorescent tube?
> >
> > I've wondered this myself.  I use the UV filter just as a precaution in
> > case there is any possibility of exposure.  The long discussion a while
> > ago on P3D didn't come to any conclusion on fluourescent lamps and UV.
> >
> > So I err on the safe side.
> > --
> > Alan Lewis
> > mailto:3-d@xxxxxxxx
> > http://members.home.net/3-d
> > Home of Weekend Stereo Projects
> > New stereo viewers & Stereo Wedding Photography
> 
> A good source of information about fluorescent lamps is the JKL Components
> Corporation web site (www.jkllamps.com).  Click on Application Notes and a
> number of ".pdf" documents are available.  In particular, "Understanding Cold
> Cathode Fluorescent Lamps (CCFL's)" is very useful.  A chart of conversion
> efficiencies shows that typically about 20% of the 253.7nm ultraviolet energy is
> converted to visible (380-780nm) light by the phosphors.  This doesn't
> necessarily mean the other 80% is emitted (much is reabsorbed and lost as heat),
> but there is still significant UV output from "white light" fluorescent lamps.
> I absolutely agree with Alan to err on the safe side.
> 
> "Lens protecting" UV filters are pretty cheap and can easily be placed behind
> the eyepiece lenses of a viewer, or Light Impressions
> (www.lightimpressionsdirect.com) sells acrylic sheets specifically designed to
> protect against UV.  "Acrylite OP-3AR" is supposed to filter out 98% of UV
> radiation.  An 8x10" sheet is $6.95.  This can easily be cut and places between
> the bulb and diffuser - might as well protect your slides as well as your eyes.
> 
> Richard Rylander
>