Pelican Nebula in SO/HaL (David McClain)

Pelican Nebula in SO/HaL

Raw frames courtesy of Deep Sky West Remote Observatory in New Mexico, USA. (deepskywest.com) Data obtained with FSQ 106EDXiii / QSI683wsg / Lodestar / Paramount MyT.

Approx 26 hrs total integration (16x1800s O-III, 20x1800s S-II, and 17x1800s H-alpha). The palette is SOO with R = S=II, G = O-III, and B = O-III, and with H-alpha serving as Luminance.

This is really a bi-color image with H-alpha Luminance. The central region appears relatively starved of S-II and dominated by O-III. The choice here is what color to make O-III. By all rights it should be a greenish color at 501 nm. But we can stretch the color-space contrast, making it more blue.

At any rate, red areas are dominated by S-II, and blue/green areas by O-III. In truth, the whole nebula is hugely dominated by H-alpha and dust. S-II and O-III make up a much weaker component of the nebula. Everything out there is dominated by H-alpha. So for a change, let's not look directly at that.

Regions where both S-II and O-III are present become a whitish color, by analogy to tri-color image where all three component colors are present.

Having learned in the previous images, I first enhanced slightly the wavelet layers 8-32 pixel scale lengths, in the H-alpha image, with diminishing amplitude toward longer scale lengths. Then I combined this H-alpha image as a Luminance control on the RGB mix of S & O. O was given a 50% strength in the G channel and 100% in B. S was given 100% in R. Then wherever magenta crept in with strong R & B, I made G equal to the minimum of either R or B, to convert the magenta into a shade of white.

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Revision completely reworked to better enhance subtle structural detail, less chrominance noise, slightly more green on the O-III, in a 3:2:3 RGB mix of S:0:0.

Original
B
Final
C

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