Re: [APML] My first light shots with Canon 20Da

[Chuck Vaughn <aa6g@aa6g.org>]

  Alan,

> Blues seem to be more white, among other little things. Does
> anyone have an explanation of why this is?

I've certainly noticed the same thing. Believe it or not I processed  
that m31 to get it to be more yellow in the middle and more blue at  
the outer edges. This was taken with the unmodified 20Da so the Ha  
response is way down which is probably why the nebulas aren't even  
pink. Now that it is modified I'll see what happens.

OTOH, tricolor TP shots of M31 and M33 show nebulas as mostly white  
with a hint of pink. I think the bright red nebulas you see in some  
shots come from the addition of H-a data.

If you care to dig deep in the APML archives, years ago Brad Wallis  
was asked what color M31 would be if you could see it. he said it  
would be mostly gray with a bit yellower in the middle and a bit  
bluer in the outer arms, not the bright yellow/orange and blue you  
typically see.

Here's a question we need to ask ourselves:

If the 20D takes normal daylight balanced images that look  
satisfactory to our color seeing eyes, why would a shot of M31 with  
the same camera not produce an image balanced the way it appear if we  
could see it in color through a telescope? I believe the inescapable  
answer is that it does take the image correctly and Brad was right.

When we see something presented in a certain way, we become  
conditioned to it and any other presentation we judge as wrong. We're  
conditioned to seeing a certain presentation of M31 based most likely  
on how a few people initially processed it; old yellow stars in the  
middle and young blue ones in the arms so it must be bright yellow  
and blue.

I've got a couple of very old M31 images taken on Konica films and  
processed and printed in a photo lab and they're all sort of a gray- 
magenta color. Yet on the same roll nebulas look completely "normal."

Another thing to consider is if the foreground star colors appear  
correct in the image, orange, yellow and blue, how could the color of  
the galaxy be wrong?

I've pretty much given up on what color these objects are supposed to  
be and look at the quality of the image overall.

Chuck
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