Re: [ATM] more on cassegrain baffling...

[Kevin Whitefire <chaosopher23@yahoo.com>]

The baffle is on the aperture, the secondary, and the
familiar primary tube.  I can see how it would work,
but I haven't the foggiest what the math would be for
such a critter.

Kevin Michael Zabbo of Eastern Iowa
Seeker of the Darkness

--- Michael Peck <mpeck1@ix.netcom.com> wrote:

> At 15:33 7/8/05, Benoit Schillings wrote:
> >
> >I was looking at the SDSS (Sloan sky survey scope)
> and noticed that they
> >used a 3 elements
> >baffle (primary, secondary + a between
> primary/secondary baffle) in
> >order to have both large
> >field and small obstruction.
> >
> >Does anybody on the list knows about this, this
> sounds like a very
> >intriguing approche but
> >do not know the theory behind it.
> 
> Here's a discussion of baffle design for the SDSS
> telescope: 
>
<http://www.apo.nmsu.edu/Telescopes/SDSS/eng.papers/19960616_Baffles/19960616.html>.
> 
> >
> >
> >Currently, to have a fully shielded/illuminated
> field, the central
> >obstruction goes
> >to 0.31 for a 10 arcmin field... I would like to
> increase the usable
> >field to 20 arcmin
> >but do not like what it does to central obstruction
> (goes up to 0.34)
> >
> 
> What are you using the telescope for? If it's mostly
> imaging 34% 
> obstruction is no big deal. Also, having a fully
> illuminated and shielded 
> field of 10' doesn't mean that you won't have a
> larger usable field. It 
> just means you'll have some vignetting or sky
> flooding.
> 
> If you have any optical design software it's not a
> bad idea to do a 
> vignetting analysis. I think one of the programs
> aimed at ATMs even does 
> automated baffle design. If I remember right in the
> example I saw it gave 
> the same solution as my spreadsheet. Perhaps the
> author just copied my 
> formulas.
> 
> Mike Peck
> 
> 
> _________________
> 
> Michael Peck
> email mpeck1@ix.netcom.com
> Wildlife photoblog! http://wildlife-pix.com
> Amateur telescope making
> http://home.earthlink.net/~mlpeck54/astro/astro.html
> 
> 
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
> 


I published my first novel!  You can get it here, from the publisher!  http://www.publishamerica.com/Their search stringbox is on the right side about halfway down.search using my name:  kevin michael zabboand it will take you right to my book page.The title is anna's blood, which also takes you there.Please order your copy soon!  I love you!

__________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 
_______________________________________________
ATM mailing list http://www.atmlist.net/