Re: [APML] anti-pollution dark red filter

["Nicola Montecchiari" <nmontec@libero.it>]

Jose,

I wanted to buy an W92-like filter but I cannot find it on glass :-(
otherwise I would have been buying it.

Nicola

----- Original Message -----
From: "Jose I. Alarcon" <JIALARCON@telefonica.net>
To: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Sent: Monday, February 17, 2003 9:47 PM
Subject: Re: [APML] anti-pollution dark red filter


> Nicola, I found the B+W 091 filter rather disappointing from my poluted
> site.
> It is a "Wratten 29". I should have bought instead a "Wratten 92" which
has
> a higher
> cut off frequency.
> Regards
>
> Jose I. Alarcon
>
> ----- Original Message -----
> From: "Nicola" <nmontec@libero.it>
> To: "APML" <astro-photo@seds.org>
> Sent: Monday, February 17, 2003 2:48 PM
> Subject: [APML] anti-pollution dark red filter
>
>
> > Dear All,
> >
> > I'm going to buy soon a dark red filter B+W 091 for my 200mm tele.
> > I read on Reeves' book that it is a nice idea do keep the filter on for
> half the
> > exposure time and than unscrewing it to get a normal colour for the
> background.
> > I was wondering if any of you tried to shoot two pictures, one with a
red
> filter
> > for all the exposure until skyfog and another one immediately after with
> no
> > filter exposed for less then the skyfog time; after that, replacing the
> red
> > channel of the second photo with the one from the first picture.
> > Does it make any sense? Would I get better nebulas?
> >
> > Cheers
> > Nicola
> >
> >
> > _______________________________________________
> > Astro-Photo mailing list
> > Astro-Photo@seds.org
> > http://seds.org/mailman/listinfo/astro-photo
>
> _______________________________________________
> Astro-Photo mailing list
> Astro-Photo@seds.org
> http://seds.org/mailman/listinfo/astro-photo

_______________________________________________
Astro-Photo mailing list
Astro-Photo@seds.org
http://seds.org/mailman/listinfo/astro-photo