Re: [APML] IR [was: M51 RGB (only)]

[Sean Walker <vze2c3z8@mail.verizon.net>]

You need an IR block filter for some of the older COLOR (RGB) filter sets
out there, and it is a must have for some refractors (TV-85, TV-102 come to
mind, as well as any less than APO scopes only when shooting Luminance
data.. it is unnecessary for reflectors though.

Sean Walker

> From: Chuck Vaughn <aa6g@aa6g.org>
> Reply-To: astro-photo@seds.org
> Date: Mon, 22 Apr 2002 09:15:33 -0700
> To: <astro-photo@seds.org>
> Subject: Re: [APML] IR [was: M51 RGB (only)]
> 
> Matt,
> 
>> Chuck, I like your California Nebula image, which is skewed to the
>> magenta by your capture of UV out to 350nm. I do not think that IR
>> or UV capture implies an unaesthetic result.
> 
> I'm not arguing aesthetics here. It's just since day 1 the CCD mantra
> I've always heard is "You must use an IR blocking filter." Now there
> is this revelation that few are using one! I wonder how many other
> revelations are out there I'm unaware of.
> 
> This new bit of info adds to the reason why CCDs are succesful under
> light polluted or moonlit conditions. Besides the increased dynamic
> range, there is practically no light scattering long of 700nm. I could
> dig up some weather satellite images that compare visible light to
> 800nm. The most mucky eastern summer day looks like a sparkling clear
> day in the mountains at 800nm. :-)
> 
> Chuck <aa6g@aa6g.org>
> 
> 
> --  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>