Re: [atm_free] Re: Sun testing a polished mirror
Tu as eu les bonnes explications. Je suis québécois, on pourra s'en parler en privé dans notre langue.
Hi everybody, have agreat day.
> De: "Ken Hunter <atm_ken_hunter@...>" <atm_ken_hunter@...>
> Date: 2003/02/28 ven. AM 11:10:57 GMT-05:00
> À: email@example.com
> Subject: [atm_free] Re: Sun testing a polished mirror
> NOT TO WORRY!
> The sun would produce a point focussed dot if it were itself a point
> focussed dot like any other star. Unfortunately for testing scopes,
> (fortunately for us) it is MUCH closer and shows up as an extended
> object here on this planet. It is about 1/2 degree wide and there is
> a formula for figuring the extended angle that it should be at the
> focal plane. I'm at work now so don't have it handy but I suspect
> that your are seeing the correct view which will also be the size of
> the moon when imaged by your scope.
> Ken Hunter
> --- In firstname.lastname@example.org, "mschaffroth <mark.schaffroth@t...>"
> <mark.schaffroth@t...> wrote:
> > Hello.
> > I'm about finished polishing my 8" f/7 blank and took it outside to
> > see how it focuses the sunlight. I was surprised (and a bit
> > concerned) that the smallest spot it could make was about the size
> > a dime (1.2cm), or perhaps a bit smaller. I thought it would make
> > pin point dot. Is what I'm experiencing expected and does it
> > indicate anything about the quality of my blank?
> > About half way through my polishing I looked at the Ronchi lines
> > they all looked parallel, but somewhat fuzzy around the edges.
> > Thanks!
> > Mark S.
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