I meant ten minutes of red -- or whatever exposure won't oversaturate. The idea is to calculate the color based on filters and exposure of whatever appropriate length. ________________________________ From: Joe Bauman <josephmbauman@yahoo.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Saturday, April 27, 2013 10:29 PM Subject: Re: [Utah-astronomy] Anyone imaging? True that it won't give you a precise spectrum with absorption lines. But you can calculate the color based on the actual color of the filter and the duration of exposure, without relying on your filtering preferences or what the processing software thinks. If two minutes of red of a particular filter value results in a particular brightness on the image, and ten minutes of blue results in a different brightness on the black and white sub, and ten minutes of green, and ten minutes of unfiltered -- you get the idea -- someone with enough optical smarts should be able to calculate the general color. -- Joe ________________________________ From: Chuck Hards <chuck.hards@gmail.com> To: Utah Astronomy <utah-astronomy@mailman.xmission.com> Sent: Saturday, April 27, 2013 10:18 PM Subject: Re: [Utah-astronomy] Anyone imaging? Patrick is right, a proper spectrum would have to be taken using a diffraction grating or prism, and it would have to be calibrated. Just shooting uncalibrated filtered images won't tell you anything but what color the image processing software thinks it is, based on your preferences. On Sat, Apr 27, 2013 at 10:02 PM, Joe Bauman <josephmbauman@yahoo.com>wrote:
Well, it might tell something if we knew the precise color of the object. -- Joe
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