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

[glenn shaw <glennshaw@alaska.net>]

Wow!! What an image THAT is!!!

My old advisor, Bart Bok would have loved to see this image.

Glenn Shaw

At 12:11 AM 7/5/04, you wrote:
>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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