NGC 6543 The Cat's Eye Nebula - 68 hours

[gorann]

12 minutes ago, ollypenrice said:

I used 120 seconds for the core in Ha. I tried longer and shorter but found that about right.

Olly

 

Superb images both of them, and this is a question to both Peter and Olly:

How did you mix in the NB data to the RGB? Just Ha to red and Oiii to blue? Or did you only use the RGB data for the stars?

Göran

[Petergoodhew]

8 minutes ago, gorann said:

Superb images both of them, and this is a question to both Peter and Olly:

How did you mix in the NB data to the RGB? Just Ha to red and Oiii to blue? Or did you only use the RGB data for the stars?

Göran

Göran, I always create an RGB image as normal and then add the Ha to red and OIII to blue in lighten mode

[gorann]

8 minutes ago, Petergoodhew said:

Göran, I always create an RGB image as normal and then add the Ha to red and OIII to blue in lighten mode

Thanks! That is what I also would try first if I have strong Ha and Oiii data (as often suggested by Olly).

[ollypenrice]

21 minutes ago, gorann said:

Superb images both of them, and this is a question to both Peter and Olly:

How did you mix in the NB data to the RGB? Just Ha to red and Oiii to blue? Or did you only use the RGB data for the stars?

Göran

In my case I did as Peter did except that I added OIII to green and to blue since it lies on the border between the two. I make two images, one HaLRGB with OIII to green and another HaLRGB with OIII to blue. I paste one onto the other and adjust the opacity till the blend most closely matches the colour of the LRGB image. If the OIII contribution is excessive I paste it onto the HaLRGB and reduce its opacity. (I work that way round rather than adding the NB data iteratively.)

For the core I will also have added Ha as luminance. I don't remember exactly how I did it but since the core is so well separated from the shell, and is circular, I'll have used layers and a well feathered eraser. A purist would make a layer mask but I'm more of a pragmatist!

Olly

[gorann]

2 minutes ago, ollypenrice said:

In my case I did as Peter did except that I added OIII to green and to blue since it lies on the border between the two. I make two images, one HaLRGB with OIII to green and another HaLRGB with OIII to blue. I paste one onto the other and adjust the opacity till the blend most closely matches the colour of the LRGB image. If the OIII contribution is excessive I paste it onto the HaLRGB and reduce its opacity. (I work that way round rather than adding the NB data iteratively.)

For the core I will also have added Ha as luminance. I don't remember exactly how I did it but since the core is so well separated from the shell, and is circular, I'll have used layers and a well feathered eraser. A purist would make a layer mask but I'm more of a pragmatist!

Olly

Thanks!

I am fully on the pragmatist side!