Red is present. In the terms of light, Yellow is a 50/50 mix of red and green. So strictly speaking you'd only need colours on your calibration to perform your tests. A green filter would eliminate red from the yellow. A Red filter would eliminate the green. I suspect they used blue because pure blue filters are particularly troublesome to produce. Pure red filters are really good. Even pure green filters are good but pure blue filters tend to let a bit of green light through as well so I suspect this is the reason for their choices
--- On Wed, 5/28/08, ensoramanda <[EMAIL PROTECTED]> wrote: > From: ensoramanda <[EMAIL PROTECTED]> > Subject: Re: [meteorite-list] Phoenix Lander and Mars Colors > To: [email protected] > Date: Wednesday, May 28, 2008, 11:01 PM > Hi Stirling > > Very interesting to see colour calibration charts...but > there dont seem > to be any shades of red....any reason for that? > > Graham Ensor > > > Sterling K. Webb wrote: > > >Hi, > > > > There is a long-running controversy about the > "true" > >colors of Mars. By "true" colors, one > essentially means: > >"What would it look like to my human eye if I was > standing > >there looking at the Martian landscape?" > > > > The Phoenix Lander can solve this problem. Like the > >rovers, it will have a color calibration target, but a > vastly > >improved one, with magnetic protection against dust > >accumulation. > > > > For those of us with the weird hobby of trying to > >reconstruct the "true" colors, here is an > image of the color > >calibration target being used at this website: > >http://news.ucf.edu/UCFnews/index?page=article&id=002400410f556ad3011a10e25439031e&mode=news > >You have to click on the tiny black-and-white thumbnail > >in the article to get the picture of the colors to pop > up! > > > > You can see the target (twice) on the lander in > this > >new photo and compare the "true-ness" of the > colors: > >http://www.nasa.gov/images/content/231350main_sol002_runout_color.jpg > > > > Things still need a tiny bit of tweaking, but > it's a > >big improvement. > > > > > >Sterling K. Webb > > > >______________________________________________ > >http://www.meteoritecentral.com > >Meteorite-list mailing list > >[email protected] > >http://six.pairlist.net/mailman/listinfo/meteorite-list > > > > > > > > > ______________________________________________ > http://www.meteoritecentral.com > Meteorite-list mailing list > [email protected] > http://six.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ http://www.meteoritecentral.com Meteorite-list mailing list [email protected] http://six.pairlist.net/mailman/listinfo/meteorite-list
