Re: ATM Apodizing Mask

["Peter" <peter@kitgear.com>]

Hi,

The article was published in the RASC Journal in April 2003. The article is
supposed to be free net but anyone who needs a copy send me a private email.

Peter

----- Original Message -----
From: Peter <peter@kitgear.com>
To: <atm@shore.net>
Sent: Friday, October 10, 2003 8:23 AM
Subject: Re: ATM Apodizing Mask


>
> In hind site I should have taken a photo of the mask because it was very
> different than your GIF image.  Yours is probably the ideal design.
>
> The mask my friend had was made from ordinary window screen material (you
> the black bug screen stuff). He used two layers, one masking the entrance
> aperture to around the 50% zone, the second was glued to the first but
only
> going down around the 80% zone. In short the central region was clear
> aperture, from 50% - 80% there was one layer of screen and from 80% - 100%
> there were two. I'm sure that the zones need to be calculated for each
scope
> design.
>
> I'll give him a call this weekend and see if I can take a photo. I'll also
> see if he can find the original article describing the construction of his
> mask.
>
>
> Peter
>
> ----- Original Message -----
> From: David Nicholls <nicholls@u030.aone.net.au>
> To: <atm@shore.net>
> Sent: Thursday, October 09, 2003 10:19 PM
> Subject: Re: ATM Apodizing Mask
>
>
> > I did a search on the S&T archive (apodize, apodizing, apodization) and
> > found only a passing reference to a book (p94, Dec 1998).
> >
> > However, in my ancient and now gone collection of S&T that covered
> > 1962-1969, I remeber an article that referred to a mask with a notched
> > inside edge - I'm going to attempt to attach a GIF image of the idea,
> > but if it's not allowed on this list, see
> > http://www.dcnicholls.com/misc/mask.gif
> >
> > It would be simple to implement as drawn.
> >
> > Obviously it's not as extensive as the Suiter design and I don't
> > remember the purpose of the original article.
> >
> > However, if the notches are sufficiently small, it might be possible to
> > get some kind of interference effect... I've not even begun to think
> > through the physics and the idea may be nonsense or irrelevant.
> >
> > DN
> >
> > On 10/9/2003 11:25 PM, David Harbour wrote:
> > > Peter,
> > >
> > > I have seen at least one article about apodizing masks in an old Sky
and
> > > Telescope. But I no longer have my old Sky and Telescope magazines,
the
> > > hundred pounds or so of which almost caused me to tangle my PA-28's
> landing
> > > gear in high tension wires because I was taking off on only one
magneto
> on
> > > one occasion. (Engage brain before flying airplane).
> > >
> > > But somewhere there must be an index to articles in Sky and Telescope,
a
> > > sort of archival directory by subject or topic category. Hope you can
> find
> > > that article, I am sure that I saw it and read it, maybe about a
hundred
> > > years ago or so, and in fact, remember how to make a rather effective
> one.
> > > But don't trust my memory; surely someone else will have that issue or
> > > issues and will respond.
> > >
> > > Davey
> >
> >
> > --
> > ____________________________________
> >
> > David Nicholls
> > Nicholls Communications
> > dcn@dcnicholls.com
> > http://www.dcnicholls.com/
> > ____________________________________
> >
>
>
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