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Subject: Re: Bubble horizon
From: Robert Eno (enoid@XXX.XXX)
Date: Thu Dec 19 2002 - 00:45:29 EST
I find a microwave oven works very well for restoring desiccant crystals.
----- Original Message -----
From: Paul Hirose <paulhirose@XXX.XXX>
To: <NAVIGATION-L@XXX.XXX>
Sent: Wednesday, December 18, 2002 4:20 PM
Subject: Re: Bubble horizon
> > The biggest drawback to the Kollsman is the reflective "pellicle" which
is
> > situated inside of the body of the unit which transmits the image of the
> > celestial body to the eyepiece. Once it starts to absorb moisture it
> > wrinkles and spoils the view. For this reason, the Kollsman is fitted
with a
> > removable cylinder which contains a desiccant to keep the pellicle dry
and
> > taut. Every once in a while, you must remove this cylinder, dry out the
> > desiccant and replace it. Unfortunately for me, I left it for to long
and
> > the pellicle self-destructed. I have not made much of an effort to find
a
> > replacement so if you ever come across a supply of them, let me know.
> >
>
> Thanks for the warning regarding the dessicant. My Kollsman arrived
> this morning. Looks like it's in excellent condition. Paint is near
> mint, image is sharp, bubble size adjustable over a wide range,
> mechanical averager checks out fine. There are two dessicators. One is
> a tiny capsule visible through the window at the top of the optical
> tube. The other is in the sextant body. They're both turning pink, so
> I guess they ought to be filled with fresh crystals. The quantity is
> so small, it hardly seems worthwhile to bake the old dessicant in an
> oven. I need to research where to buy the stuff, though.
>
> When I was in the service we ordered dessicant by the gallon can. It
> was used to keep radar waveguides dry. New parts often arrived packed
> with little pillow bags of dessicant as well. They were usually
> discarded, but my boss saved them to keep humidity down in his gun
> cabinet.
>
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