Re: [APML] Scorpius, Sagittarius, and the Milky Way

["Bobby Middleton" <bobm@koyote.com>]

Beautiful!!
Excellent color, grain, and resolution. These are good Wei-Hao.
Bobby Middleton


>
> Hi Wei-Hao,
>
> what a great image. Wonderful work and an interesting description of
> your processing methods.
>
> Best regards
> Andreas
>
> :=============================
> : Andreas Roerig
> : http://www.andreasroerig.de
>
>
> Wei-Hao Wang <whwang@gmail.com> schrieb am 05.07.2004, 10:11:53:
> > ALOHA,
> >
> > A new image is in
> > http://www.ifa.hawaii.edu/~wang/gallery/picutres/sco_sgi_milkyway.htm
> >
> > To correct the vignetting pattern, I used a little crappy but quick
> > flat field method.
> >
> > As I introduced my flat field technique to you about half year ago, I
> > took several
> > images of daytime sky and average them to make a flat image.  The old
way is
> > to nonlinearly match this flat with the sky background in a real
> > astronomical image
> > and then divide the image with the matched flat image.  This method
works quite
> > well.  I had showed the results on my Orion mosaic to you.  However,
> > this technique
> > may be a little difficult for most people since it requires some
computer
> > programming.
> >
> > In order to see if things could be more simple, I divide the image with
the flat
> > directly (without any background matching).  The result is the image
above.
> > I have to say, this flat fielding is not perfect but the residual
> > vignettign pattern
> > can be so easily fixed in PhotoShop.  I think this is worth trying.
> > You don't need
> > to write a C++ program.  All you need is to take a picture of daytime
sky and
> > find a image processing software that does division (PhotoShop doesn't).
> >
> > Cheers,
> >
> > Wei-Hao
> >
> > -- 
> > ________________________________________________________________
> > Wei-Hao Wang  :)
> >
> > Institute for Astronomy at University of Hawaii
> >
> > Address:
> > 2680 Woodlawn Drive         Personal Website:
> > Honolulu, HI 96822             http://www.ifa.hawaii.edu/~wang
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