The Iris Nebula 26.75 Hours

[sreilly]

This image has been a challenge. I started out with just RGB data and then realized that the fine details wouldn't be displayed well without a good luminance image. The original image had 13 luminance images used and it did little to help. I managed some additional images, 39 of them, and re-processed all the data in PI. One big difference this time was finally getting a handle on using cosmetic correction to get rid of the hot/cold pixels.

Processes used:

Calibration using Master Dark (115 frames for 2x2, 104 for 1x1)
Master Bias (400 bias for 1x1, 500 for 2x2)
Master Flats (36 each for East/West Master)

Images Calibrated using  Image Calibration
Apply Cosmetic Correction (Removal of Hot/Cold Pixels)
Star Alignment for RGB and the Luminance
Combined Red, Green, Blue, and Luminance Masters
Crop resulting RGB Master, Crop Master Luminance
RGB image requires Background Neutralization (on this RGB image it also corrected the color balance)
Both RGB and Luminance masters stretched using Masked Stretch
Created a Star Mask for Both Masters
Apply Star Mask to Luminance and used HDRMultiscaleTransform
Use LocalHistogramEqualization on inverted masked Images
Used Curves to increase Saturation in the RGB image
Used Dynamic Alignment to register both master images
Combined to create the L+RGB image.

Finished Image can be seen in various sizes here http://www.astral-imaging.com/NGC7023-RC2.html

[Giorgio]

Really very beautiful is very deep
Giorgio. 

[sreilly]

Thanks Giorgio.

 I posted one last version of this image on my web page but the process I used was outside of PI. I wanted to work on only the low s/n areas and couldn't figure out how to do that in PI. I made a copy of the original image, ran a noise reduction process, and created a mask in another layer then inverting a copy of the image as a mask. I used levels to adjust so the protected area was dark (black) and areas to apply the mask was light (white).

I would very much prefer to find a way to do this in PI only. I'm trying very hard to not use any software outside of PI for the calibration and processing of my images. I'm 99% of the way there I think. There's still much to learn.