Re: [APML] Esthetical effects filters

["Kevin Wigell" <kwemail@twcny.rr.com>]

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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