I did try Wes' trick but it didn't work for me. I split the image
into R, G and B, aligned and then recombined them. I still had a
blue ring around the edge. I'll try it again on a different Jupiter
and see what happens.

I have seen the blue ring on many Jupiters taken by others. It is
indeed an atmospheric refraction effect – the index of refraction of
the atmosphere is larger in the blue than in the red – normal
dispersion. I think that means that the blue image is a bit larger
than the red and green, but I've not measured the three components'
sizes to confirm that. I believe I sometimes see the same problem
with lunar images – the blue channel seems out of registry with the
rest of the image.

Jupiter is a very difficult subject for me, both in acquisition and
in processing. I must have taken several hundred frames before I was
even able to capture the GRS.

Dennis

--- In ImagesPlus@y..., Ken Florentino <kflor@p...> wrote:

Dennis,

Have you tried the trick Wes mentioned about separating the colors,

aligning them and recombining? I notice

atmospheric chromatic abberation in the image you put up there.

Give it a try. I think Mike is going to put a 1 step menu

item to do that in a future release.

Sometimes one channel (usually blue) is larger than the rest and an

easier way to scale it for these (and other) purposes

would be nice. Something that works the way the current sliders do

when enabled. Every time you make an adjustment,

it updates the image and only when you are satisfied with the size

would you hit the Reset button.

Ken

I did try Wes' trick but it didn't work for me. I split the image
into R, G and B, aligned and then recombined them. I still had a
blue ring around the edge. I'll try it again on a different Jupiter
and see what happens.

If it goes all the way around the edge after alignment, then you will have to resize it a bit. That's the hard part is how
much. That's were using copies (since resize isn't undoable) is helpful.

Ken

Hi Dennis ,


"I did try Wes' trick but it didn't work for me"

Actually Mike Unsold told me how to do it and I think Ken Florentino had
something to do with figuring out how to do it .

You can down size the blue image slightly also .

Thanks,

Wes



I did try Wes' trick but it didn't work for me. I split the image
into R, G and B, aligned and then recombined them. I still had a
blue ring around the edge. I'll try it again on a different Jupiter
and see what happens.

I have seen the blue ring on many Jupiters taken by others. It is
indeed an atmospheric refraction effect - the index of refraction of
the atmosphere is larger in the blue than in the red - normal
dispersion. I think that means that the blue image is a bit larger
than the red and green, but I've not measured the three components'
sizes to confirm that. I believe I sometimes see the same problem
with lunar images - the blue channel seems out of registry with the
rest of the image.

Jupiter is a very difficult subject for me, both in acquisition and
in processing. I must have taken several hundred frames before I was
even able to capture the GRS.

Dennis

--- In ImagesPlus@y..., Ken Florentino <kflor@p...> wrote:

Dennis,

Have you tried the trick Wes mentioned about separating the colors,

aligning them and recombining? I notice

atmospheric chromatic abberation in the image you put up there.

Give it a try. I think Mike is going to put a 1 step menu

item to do that in a future release.

Sometimes one channel (usually blue) is larger than the rest and an

easier way to scale it for these (and other) purposes

would be nice. Something that works the way the current sliders do

when enabled. Every time you make an adjustment,

it updates the image and only when you are satisfied with the size

would you hit the Reset button.

Ken

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The blue crescent on Dennis's Jupiter image can be removed by
shrinking the size of only the blue component using
Geometric/Transforms > Scale set to 0.99 followed by an auto
alignment of the split color images. The fixed image is posted in the
Analysis folder and is called Blue Channel Scaled 0.99.

Mike

Very detailed instructions for fixing a blue ring in an image of
Jupiter can be found in the Files / Processing Instructions folder. A
fixed version of Dennis's Exponential Jupiter image is in the
Photos / Analysis folder called Blue Channel Scaled 0.99.

Mike