Re: [ATM] Slit and source arrangment

["Bob May" <rmay@nethere.com>]

When you're investigating something odd, you always go to the
absurd to see easily what the problems are.
That is what Dale almost did.  He should have also gone the same
distance vertically as he did horizontally.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net

----- Original Message -----
From: David Harbour <stainless_steel@suddenlink.net>
To: Jerry <wa4guu@verizon.net>; 'ATM list' <atm@atmlist.net>
Sent: Saturday, April 26, 2008 8:27 AM
Subject: Re: [ATM] Slit and source arrangment


> Jerry,
>
> Thank you. I already had a pretty good idea of what you meant;
but what I
> would like to know is, why would anyone do this; also, I just
replied to a
> post by Dale about a K.E. and slit seperation of 16". This is
crazy to me.
> Are we trying to make telescopes, or write inanity here? No
offense
> intended. I do understand what you are saying; I am just
wondering why we
> are continuing this thread, inasmuch as everyone knows the
right thing to
> do. We are all rocket scientists here, who have made very good
optics and
> mountings; it seems to me that we are continuing unproductive
threads. What
> is this pursuit really about- inasmuch as we already understand
these
> applications, and their principles?
>
> Thank you, Jerry-
>
> R-101
>
>
> ----- Original Message -----
> From: "Jerry" <wa4guu@verizon.net>
> To: "'David Harbour'" <stainless_steel@suddenlink.net>; "'ATM
list'"
> <atm@atmlist.net>
> Sent: Friday, April 25, 2008 6:24 PM
> Subject: RE: [ATM] Slit and source arrangment
>
>
> I was speaking specifically of a separate knife separated
laterally from the
> slit. You want the image of the source at the same height as
the source, not
> above or below the source height.
>
> For this to show correctly you may have to restore line breaks
if the are
> removed
>
>
> X = source
> O = image of the source
> I = knife
>
> X  OI   No tester induced astigmatism ying yang.
>
>
> X
>    OI   Tester induced ying yang may be visible.  Tester
induced astigmatism
> is nearly at 45 degrees to horizontal mirror diameter under
test.
>
>
> If that doesn't display right I will try again.
>
> Jerry
>
>
>
>
> -----Original Message-----
> From: David Harbour
> Jerry,
>
> Please try to be a little more unequivocal in language, here. I
am having
> trouble, being certain, about what you are saying.
>
>
> ----- Original Message -----
> From: "Jerry"
>
>
> >
> > A ying yang may show if you have both a lateral and vertical
components to
> > the off set of the returning beam. By this I mean that the
line from the
> > source to the image of the source is diagonal to the length
of the slit
> > and
> > knife. The tester induced astigmatism would be across a
diagonal diameter
> > of
> > the mirror.
> >
> > Just be careful to adjust the tester to have the return beam
at the same
> > elevation as the light source.
> >
> > I prefer slit testers because a limit can be set to the light
that comes
> > by
> > the knife on the bright side of zones. I also like that a
fixed source
> > will
> > double the knife readings. Of course all this is really not
so important
> > as
> > knowing how to use whichever tester is in use.
> >
> > Jerry
> >
> > _______________________________________________
> > ATM mailing list http://www.atmlist.net/
> >
>
>
>
>
> _______________________________________________
> ATM mailing list http://www.atmlist.net/
>

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