Re: [APML] Stacking Software

[Jerry Lodriguss <jml@astropix.com>]

>
>Maybe I am not doing things right, but when I use registar the images get 
>combined
>in registar and I don't need Photoshop for this. I only use Photoshop for 
>color
>balance, etc.. When I register two color images, I get a B&W registered 
>image and
>then I go to the combine command to get the final color image that is the
>combination of the two originals.

You're doing things correctly, but that's not really a black and white 
image you get when you register the two color images, it's only a display 
of a single channel so the stars that are not present in both frames can be 
shown with a different color.


>  Regarding the sky fog limit, do you know the
>limit for an f:6 optical system using Elitechrome 200 slide film?


 From a dark sky site you could try 45 - 60 minutes, but exposures will 
vary depending on the brightness of the night sky where you are shooting, 
and the brightness of the object you wish to photograph and the sky-fog 
limit will vary depending on the darkness of the site, any local light 
pollution, natural sky-glow, solar cycle, transparency, elevation, true 
T-stop of the optical system (Transmission-Stop vs the stated F-stop), and 
a number of other factors.

You simply have to test it with your system. These times are starting 
points only.

Also, for E200, it's better to overexpose it a little bit than to have the 
sky really black because it will be easier to scan.

Jerry




Astronomical photography: http://www.astropix.com




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