Re: [APML] Exposure time with filter

["Jim Ives" <flyboy9990@earthlink.net>]

Hi Robert yes I agree. I've been using a Hutech LPS filter for 1hr 20min
shots with TP @ f3.3.  I haven't tried it with color film yet but hope to do
so soon.  I have a B33 shot that needs finishing.
    I would like to try the tri-color imaging with this scope and it looks
like the Wratten filters are my only option to get around a $500 filter set!
Jim
----- Original Message -----
From: "Robert Reeves" <reeves10@swbell.net>
To: <astro-photo@seds.org>
Sent: Thursday, November 28, 2002 1:22 PM
Subject: Re: [APML] Exposure time with filter


> > It does make sense Robert thanks. Sounds like a low transmission %
though!
> > Maybe better suited for Schmidt cameras than my f/3.3 Takahashi.
> > Jim
>
> Well... yes, the #92 may pass only 3/4 of the H-Alpha, but realistically
how
> much is that?  That's only 1/2 f/stop less.  Small potatoes really.
> Remember that the filter is also reducing light pollution by 90% or more,
so
> the exposure can be MUCH longer, way, WAY more than making up for the 25%
> loss of the H-Alpha wavelength.  It really does alow shots that would be
> impossible on film without the filter.
>
> Robert Reeves                      reeves10@swbell.net
> 520 Rittiman Rd.                   www.robertreeves.com
> San Antonio, Texas 78209    210-828-9036
> USA                                     29.484  98.440  200 meters
>
>
> --  APML Archives at <http://astro.umsystem.edu/apml/>  ---
>              Unsubscribe at <majordomo@seds.org>
>


--  APML Archives at <http://astro.umsystem.edu/apml/>  ---
             Unsubscribe at <majordomo@seds.org>