Re: [APML] Esthetical effects filters

[Vicent Peris <vicentperis@ya.com>]

Perhaps a homemade filter with two perpendicular wires can
do the job ;-)

Vicent.


At 18:38 07/05/2003 -0400, you wrote:
>Emmanuele Sordini wrote:
> > I occasionally run into some widefield piggyback pictures (i.e. no
> > telescopes involved, only telephoto lenses) which have some pleasing
> > effects on the stars in them. In particular:
> >
> > 1) Some of them have the brightest stars which are bloated way beyond what
> > you could expect from their apparent magnitude. What kind of filter is 
> used
> > to achieve that effect? Perhaps by utilizing what is called a "fog filter"?
> >
> > 2) In some others (but fewer anyway) the brightest stars have many nice
> > rays/points. Since those rays do not come from a telescope secondary
> > mirror's spider vanes, what filter is used in this case? Perhaps a n-point
> > star (n=6, 8...) filter?
>
>You mean like this photo, taken with a 200mm telephoto lens?:
>http://www.kwastronomy.com/NGC_7000.htm
>
>No filters were used. The spikes on Deneb are reflections off the iris (I 
>had the lens stopped down to f/8 for sharper stars).
>
>The bloating of Deneb is just due to its brightness.
>
>Kevin Wigell
>www.kwastronomy.com
>
>
>
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