From: Alan Friedman <alan@greatarrow.com>

Date: July 28, 2008 1:50:28 PM MDT

To: Astro_IIDC@yahoogroups.com

Subject: Re: [Astro_IIDC] Monochrome???

Hi Dave,

I'm not sure I am following your argument, but I would recommend the monochrome camera over the color camera for all serious imaging applications where maximum resolution is one of the goals. 

Being able to use the full resolution of the monochrome chip when imaging through color filters allows you to take advantage of the steadying effect that comes from imaging through narrow bands of the visual spectrum. Granted, this advantage will diminish in the wonderful steady air from southern Florida, but from my location, you can see a palpable improvement (1-2 points) on the Pickering scale when imaging through red and green filters as opposed to full spectrum white light. A luminance image constructed from red and green will improve the sharpness of Saturn and Jupiter images while preserving an accurate aspect of the planet. For Mars, you really do need to include the blue data in luminance or you will wind up with a loss of cloud detail in the final image. For the moon, most imagers are achieving their highest resolution images in good seeing through green and (when the seeing is exceptionally good) blue filters due to fact that resolution increases as wavelength of light decreases.

My .02, Milton's take on this might be different.

cheers,

Alan

On Jul 28, 2008, at 3:24 PM, doodlebun wrote:

-Milton,

If I understand your explanation, the workflow you are recommending
is:

1. Capture R, G, and B Monochrome movies with the DMK21AF04
2. Do NOT select USE MONOCHROME CHANNEL FOR SHARPNESS AND ALIGNMENT.
instead just change MONOCHROME to RED (or G or B) for processing a
movie through the red filter.

The reason would be to speed up the stacking in the step leading to
display of the confidence setting histogram screen?!?

After you accept the subset of frames in the histogram screen, the
stacking begins, which is rather slow. Are you saying the steps
stated above will speed up that process, producing a finished stacked
image ready for wavelet adjustments, much sooner with no downside of
the technique?

NOW CONSIDER THIS THEORY OF MINE ABOUT COLOR VS MONOCHROME.

If you scan the net for planetary pictures taken with Imaging
Source cameras you will notice only a tiny fraction of them will be
taken with color cameras like the DBK or DFK series. 95% will use the
monochrome with filters.

Now here comes the heresy from Florida in the form of axioms.

1. The surface brightness of Saturn is rather dim, which makes a LRGB
approach prudent.

2. The luminance frame of a Saturn image is much brighter and with
higher resolution than the R,G, or B. filtered image in the
DMK21AF04. This makes the LRGB combo image the way to go.

3. The surface brightness of Jupiter is so high that taking Luminance
frames is a waste of time. The resolution of a processed luminance
image is no better than a processed red image.

4. A color camera like the DBK21AF04 will produce images of Jupiter
that are indistinguishable from monochrome RGB combined images.
Monochrome images must be rushed to finish in less than 3 minutes.
Jupiter's moons like Io move so fast that the RGB images will never
register over each other anyway, making the color camera the logical
choice.

In conclusion:

Saturn: use DMK21AF04 with LRGB filters
Jupiter: use a DMK21AF04 alone and color balance with Astro IIDC.

Dave
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