M42 RELOADEDCamera: Canon EOS Digital Rebel XSi - Filtro Type I
Telescope: William Optics 132 FLT - Focal Length 925 mm - f/7
Number of images:
217 x 8 seconds
62 x 2 minutes
38 x 4 minutes
15 x 10 minutes
Total Time 7:30 hours
ISO 800
In the last PixInsight workshop in Buenos Aires, Carlos Milovic teach us about how to eliminate the noise that generate the Canon XSi in exposures longer than 4 or 5 minutes when the temperature is highest than 25ºC, then I decided to reprocess the image that I had with that defect (15x10 minutes) and then recombine with the rest with HDRComposition Tool.
The Pattern is not removed with dark subtraction and the method consist in applying Fourier Transform to the image, and correct what causes the pattern in the DFT_magnitud image and then to combine again with the DFT_phase using the Inverse of Fourier Transform, and "magically" the lines disappear.
The image looks like this. Should be deleted the two short vertical lines that appear on the horizontal line. It was magic for me, thanks Carlos.
I did this after debayer because it works better.
Following is the integration of 15x10 image and HDRComposition with the rest of images
The main steps in processing HDR were:
BackgroundNeutralization and ColorCalibration
Deconvolution with PSF and StarMask to protect the core of big stars.
HT followed with MaskedStrech
Protecting with starmask apply HDRMT
Noise Reduction with ACDNR to Lightness and Chominance
HDRMultiscaleTransformation protecting background and stars cores with rangemask.
LocalHistogramEqualizations protecting stars halos with exclusion Mask
CruvesTransformation variating rangemask to recover color an contrast in bright areas
Noise Reduction with ATWT
ColorSaturation
SCNR
ACDNR
Final Curves
Saludos,
Alejandro
