Re: ATM 3-Vane or 4-Vane Spiders

["Richard" <richas@earthlink.net>]

You mean you actually did an experiment to answer a question?  Why didn't
you just look up the answer in the ATM 3 volume set?  Then you would have an
authoritative answer that you could depend on instead of a possibly false
observation!

----- Original Message -----
From: "Jim Fitch" <jf@arn.net>
To: "'Nils Olof Carlin'" <nilsolof.carlin@telia.com>; <Myosin@aol.com>;
<scot@vquill.com>; <atm@shore.net>
Sent: Tuesday, October 09, 2001 12:49 PM
Subject: RE: ATM 3-Vane or 4-Vane Spiders


>
> >
> > > The mass of the vanes radiates to the sky and is a bit
> > > cooler than ambient air and consequently the vanes are
> > optically much
> > > "thicker" than their physical thickness.
> >
> > Anyone seen this in reality?
> > Nils Olof
> >
>  I insulated two vanes of a four vane spider with Black Flocked Paper to
> see if I could demonstrate any thermal effects on the diffraction
> spikes. Even though the insulated vanes had a thicker profile the
> corresponding spikes appeared dimmer and were thinner and longer. Unless
> I looked at the wrong spikes (I don't think so) I think the temperature
> difference of the vanes does effect the size of the diffraction spikes.
>
> Any other findings?
>
> Jim Fitch
> Amarillo, TX
>
>
>