LRGB technique

In this page, I explain my method to add the Luminance image with the color frames. The main technique comes from Rob Gendler using PhotoShop. The Luminance frame can come from several images combined with a Sigma software (RCConsole, R. Gralak, MaxIm DL CCD 4.......) taken with one or several different filters : Clear, R, G, B, Hα, OIII, SII, NII....................

    For my Luminance frames, I use the following filters :

13nm Hα CCD nebular filter ( Ø 1.25" )

13nm OIII CCD nebular filter ( Ø 1.25" )

13nm SII CCD nebular filter ( Ø 1.25" )

IR Blocking Clear filter ( Ø 1.25" )

Astrodon™ 1:1:1 Tru-Balance™ LRGB Filters ( Ø 1.25" )

    For my RGB frames, I use the following filters :

Astrodon™ 1:1:1 Tru-Balance™ RGB Filters ( Ø 1.25" )

To combine and to prepare my LRGB frames, I use 3 softwares : SB CCDSoft 5, MaxIm DL CCD 4, PhotoShop.

To avoid a very long text, I prefered to show the frames from the softwares with all the steps. The image used is my M-27 Dumbell nebula.

I) I Prepare the RGB images :

The first step is to align and to resize the RGB frames at the same size of the Luminance. In the following case, my M-27 luminance has been taken in binning 2x2, the RGB frames in binning 3x3, at the same focal length with my SBIG ST-10XME.

To align my RGB frames, I use MaxIm DL CCD 4 :

The Auto - Star matching works fine but sometimes the Manual 2 Stars is necessary if the first failed.

After that, I can resize my RGB frames with MaxIm DL CCD 4 :

II) I combine the  RGB images

Now, I can combine my RGB frames. I use SB CCSoft 5 for this work, better. I open the 3 images,  with the color combine tool I select a 1:1:1 ratio and I open the preview image to see if all is OK for the colors. After that I combine them.

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