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Old January 11th 08, 12:42 AM posted to alt.binaries.pictures.astro
Ralph Hertle
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Posts: 1,193
Default ASTRO: M1 color composition

DvandenH:

The images are beautiful to see.

I am a new guy to celestial imaging, however, I have lots of visual and
computer imaging skills.

From my lurker's viewpoint I find that the lightened version has lots
more bluish white in the central area, however, the structures visible
that are green in the former image are not visible in the lightened version.

The bluish white image shows a little more at the edges of the
structure, and that is always an area of interest to me. I try to see
the extent of the object, and I am always suspicious of images of
galaxies that have a sudden cut off of light at the outer edges. On the
other hand maybe the objects do in fact have a more pronounced boundary
edge and do not fade gradually at the greater edges.

The bluish white version has better background blacks, and more visible
tiny stars, however, all the stars are wider and appear to be slightly
out of focus.

The bluish white version doesn't appear to be a lightened version with
greater visible light intensities. Did you raise the visible intensities
of some filtered images and not others? Also, if the bluish white
version is slightly out of focus does not that ruin some of the
modulations of the lighter lights?

My computer graphics card and monitor can display 255^3 possible color
hues, and it has [claimed and not possibly actual] 1000:1 displayed
steps of contrast. What I often do is to plug in my big high-res CRT
monitors that do not have deep blacks and that have lots better faded
visible contrast areas than the LCD screen monitors.


Ralph Hertle