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IC5146
The Cocoon Nebula in Cygnus
Three weeks ago we posted a monochrome image of the Cocoon so I won't repeat the technical info on the subject. You can review that by going to the "Recent Photos" link below. The objective this week is to display a color image of the same object and compare the two images.
Both images were 20 min exposures taken through the 16" scope operating at f3 with a focal reducer. You can argue about the "reality" of the color but there is little doubt that nothing was lost in the way of either limiting magnitude or resolution. In fact, I would argue that the color version is better in both respects.
How can this be as the color version "sees" through filters which are supposed to reduce the sensitivity significantly and the resolution is degraded by the need to use multiple pixels to produce the color image.
My only guess is that the focal reducer has enough negative effect that the advantages are lost by the time the image is processed. I only use it when the object is too large to produce a useful picture without it. Even on a scale this small, the coma is obvious and happens to be worse on the monochrome image. This is probably just a fluke resulting from the lack of critical focusing which is no trivial problem at f3.
For the most recent Astrophotos of
the Week... RECENT PHOTOS