[Author Prev][Author Next][Thread Prev][Thread Next][Author Index][Thread Index]
Re: [ATM] Spider vane color?
Doug,
I tend to agree with Don. The smoother and shinier, the better.
Scatter is what you want to avoid and in my opinion will be more
harmful. Consider the moon 2 deg. off axis. The light reflected off
the vane will hit the mirror or right next to it, but will be
reflected onto the side of the tube or back out the top away from the
secondary. I think even flat black will scatter more light directly
into the eyepiece.
Scott Ewart
----- Original Message -----
From: "Don Clement" <clement.focuser@verizon.net>
To: <atm@atmlist.net>
Sent: Thursday, May 04, 2006 4:22 PM
Subject: Re: [ATM] Spider vane color?
I wonder if the best thing would be to leave the polished finish on
the SS
spider vanes. Reflected light from the spider vane sides would be
diverted
harmlessly outside a truss or onto absorbing sides of a tube wall. An
example is a 3" to 2" adapter I make. The lower ½" of the 1" long
adapter is
smooth sided 45 degree cone. Light is reflected from the smooth sides
of the
adapter into the deep internal pleats of a flat black bellows. The
result is
almost total absorption of the reflected light by the light trapping
pleats
of the bellows. When looking up into the adapter the surface appears
more
black than any thing I have experienced. The reflective cone and light
trapping pleats is blacker than even good black velvet surface.
Don Clement
Running Springs, California
> I'm rebuilding a 6", and I've made a spider from 0.005 inch
> stainless shim stock, 1/2 inch wide. It makes GREAT vanes
> -- very thin, very strong. BUT -- of course, they're
> polished stainless, but I hesitate to paint them black. I'd
> have to rough them up (not easy to do smoothly), and they'd
> end up thicker. And, at only 5 mils, paint will
> substantially thicken them. The spider is in a full tube,
> so they can't really reflect any light anywhere interesting
> - so I think leaving them bare is best.
> Suggestions/recommendations from the group??
> Doug
>
>
> _________________________________
> Dr. Douglas N. Arion
> Hedberg Distinguished Professor of Entrepreneurial Studies
> Professor of Physics
> Head Coach, Ice Hockey
> Carthage College
> 2001 Alford Park Drive
> Kenosha, WI 53140
> 262-551-5864
> 262-551-6208 (Fax)
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
_______________________________________________
ATM mailing list http://www.atmlist.net/
--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.1.385 / Virus Database: 268.5.2/329 - Release Date:
5/2/2006
_______________________________________________
ATM mailing list http://www.atmlist.net/