[APML] Re: Dark-Skies Poster (was: Poster-Size Prints?)

["Kevin Wigell" <kwemail@twcny.rr.com>]

Jerry Lodriguss wrote:

> Don't you think it is a little bit deceptive to use a long exposure photo 
> that shows color in the Lagoon nebula ( which is not visible to the naked 
> eye) as well as stars past the visual limiting magnitude and compare it to 
> a "retouched" image showing the effects of typical city light pollution? 
> Also, if the city image had that much light pollution, the sky would have 
> some color from it, and wouldn't be black.
> As an astrophotographer I know you are cheating on one hand, and as a 
> non-astrophotographer I know you are cheating on the other hand also 
> because it says the image is retouched.
> If you are going to do this kind of comparison to make an example to 
> convince people, it should be intellectually rigorous.

Jerry, this "poster" was the end result of a joint project of several people, including other members of the IDA and SELENE-NY, as well as Dr. David Crawford, co-founder of the IDA. I went through numerous (dozens) revisions of the images and the text before arriving at this final product, which was personally approved by Dr. Crawford. Yes, the points you raised were discussed, extensively. In no way is this poster intended to represent an accurate or scientific portrayal of what the human eye can see from a dark sky site vs. a heavily light-polluted site. I think we all know the difficulty in trying to reproduce with a photo the night sky as it appears to the human eye/brain. As I said, this was discussed extensively at the time, and while we never arrived at unanimous agreement, this was the final product.

We also did discuss the color of the night sky from a city. The consensus was that, even though the sky background is much brighter, it appears black to the eye because of the contrast with lights, lighted building, signs, etc. Actually, if I had been completely honest about the "city" image, it would be a featureless orange-pink, as probably none of those stars would be visible from a heavily light-polluted area.

Everything you said above is true. However, if one admits he is "cheating" (as in the notation that the "city" image is retouched), then is it still cheating?  This poster is not intended to be intellectually rigorous. It is intended to be an educational device to demonstrate to the layperson the vast difference in the sky from a dark-sky site (which probably most people in the U.S. today have never really seen) versus a heavily light-polluted site.

I realize that many may not agree with my final result, but it was produced by means of a cooperative process with many others, experts in the field of light pollution, if not astrophotography.

Kevin Wigell


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