From: "Tim" <tjp314@pacbell.net>

Date: October 31, 2005 7:48:54 AM MST

To: Astro_IIDC@yahoogroups.com

Subject: Re: Colors are making me mad!

duane:

Sorry you're having so much trouble!  One possibility is that maybe the color filters were 

intended for visual use, and so don't effectively block other colors from being transmitted 

to the CCD even with a IR blocker in place.  

But it sounds more likely that the ccd isn't sensitive to blue (most are more sensitive to red 

light).  It isn't unusual to have to take exposures much longer through blue than green or 

red.  Even with a good exposure, the blue image shouldn't show much in the way of detail, 

except at the limb, polar caps and hoods.  I remember years ago watching Don Parker 

image Mars with his old LynxxPC camera.  Red exposures were a fraction of a second in 

length, green a second or two, and blue was 25 seconds long! (but what was most 

amazing is that Mars held still that long!).

So, I'd try setting the exposure times individually for each filter, and then adjusting the 

levels in Photoshop individually after the channels are combined.  I set my exposures so 

that the histogram peak is about halfway to 2/3 of the way toward the high end, so I avoid 

saturating the bright areas on the planet.  

Depending on the scope you're using, you might also want to adjust the focus for each 

filter as well.  Probably only necessary for an achromat, though.  I have a Jaegers 6" f/10, 

and even with a contrast booster and IR block filter in place, I get goofy colors at planetary 

image scales.  But since I don't have a monochrome camera (except the DSI Pro, but that's 

a topic for another forum, and a much lower quality imager than the Flea I use most of the 

time), I haven't taken the time to experiment with refocusing for different colors.  

best,

-Tim.

--- In Astro_IIDC@yahoogroups.com, "Duane" <macastronomer@m...> wrote:

I am trying to shoot with this B&W camera, and I must be doing something wrong.

First off, I am having a lot of difficulty trying to get an exposure that will work with all 

three 

colors. If I expose the Red properly, the blue is non-existant. If I expose so the blue 

shows 

ANYTHING, the Red is blown way over-exposed.

OK, so I shot a few Mars shots and I stack them up. These are straight from Astro IIDC 

and all 

three shots have the same camera settings. Put the red in the Red channel, Blue in the 

blue 

and green in the green. What do I get? A very mucky red color that doesn't show any real 

white or come close to the colors I get with color camera.

This time I did shoot  through an IR filter for all exposures.

Am I missing something there?

Please help me before I send this camera back for a color version :)

Duane