Hi,
M 16 for august monthly contest.Image information: Object: M 16
Camera: Canon 450 Digital Rebel XSi - Filtro Type I
Telescope: William Optics 132 FLT - Focal Leng 925 mm - f/7
Images: 26 x 10 minutes. ISO 800
Total time: 4 hours y 20 minutes
Program: PixInsight
Comments: Guided with Orion 100 mm and SSAG from Trenel, La Pampa - Argentina.
This time I have used Batch preprocessing script to calibrate and align using dark, bias and flat.
ImagesIntegration with Winsorized Sigma Clipping as rejection algorithm with values of 4 and 2 for low and high respectively.
Result of the integration with STF (RGB not linked) applied:
DynamicCorp to eliminate borders:
In order to see what is happening in the background and how much information there are, clone the image and apply HistogramEqualization.
Its seems will be needed to use CanonBandingReduction for Horizontal banding.
Besides there is some faint nebulousness that I will try to highlight:
Take a small preview to use in BackgroundNormalization, and apply STF again:
After BN, CBR with values by defect to eliminate horizontal banding:
After CBR I inspect a clone of the image with HistogramEqualization and seems to be needed a DBE.
For DBE, first apply the samples over the clone to see easily where to put them and then generate a new DBE instance to be applied over image.
Followed, Color calibration using the same preview used for BackgroundNeutralization as Background Reference and the image as Reference image:
The following step will be Deconvolution but previously build a mask to protect some stars cores. The mask is made extracting CIE X from the image and applying HT and MMT on it for intensify stars, and then generate a rangemask:
Generate the PSF to be used in Deconvolution, and by trying and error find the best parameters, varying mainly Deringing. Apply Deconvolution with the previous range mask protecting stars cores.
I found that some stars even with the mask active, have too intense color, and inspecting color by color can be seeing that some channel where affected differently by deconvolution:
Then I looked for different Deringing values for each channel and applied separately, always protecting stars cores with rangemask and the result was better:
Before stretching I do some noise reduction using ATWT. For that built a luminance mask to protect bright areas.
Apply using k-Sigma (not showed in the preview) that gives very good result in my pictures:
Now MaskedStretch increasing the number of iteration until 200 but with low target, only 0,1. And after that, HT to crop a little in shadows:
New stretch, this time with HT without masks:
In order to achieve better contrast in the bright areas use HDRMultiscaleTransform protecting stars cores with rangemask:
HDRMT once again but this time in 4 layers Deringing in large-scale:
For ColorSaturation, build a new rangemask to protect background areas that increase too much the noise when saturate. My choice is saturate mainly blue and orange:
Without mask apply SCNR to eliminate greens:
As ColorSaturation increase the Chrominance applied ACDNR with the "aggressive" Multiscale Rescursive Prefilter without mask:
Before:
After:
Now look for more details using LHE. Star protection is needed in order to avoid stars increase the brightness. I use Truncation in StarMask Tool to have very well protected the stars cores and surrounding areas:
To increase the brightness of faints nebulae in the background use ExponentialTransformation with high smoothing:
MMT for better definition of structures protecting stars with starmask to avoid the increasing of bright:
The ExponentialTransformation tool increase the noise a little. Then I apply a new reduction using MMT in layers number 2 and 3:
With a new starmask protecting nebulae apply MorphologicalSelection to stars to reduce them a little:
The main nebula has zones where the contrast can be improved. Build a rangemadk that allow work only in the Bright region and apply LHE:
Before:
After:
CT to increase again the saturation lost during LHE. With the same mask in order to affect the the bright region:
Finally a little decrease of RGB channels:
Final result after resample to 1600x1060 and Signature with DrawSignature Script:
Saludos.
