Hello everyone
I present you with my entry for this month's contest: Galaxy NGC 891 in Andromeda.
The image was made from my suburban location near Bruges Belgium.
Sky quality : 20.38 mag/arcsec^2
Telescope : 14.5 inch f/9 Ritchey-Chretien
Mount : Paramount ME
CCD : Sbig STL-11000M
Filters : Baader L,R,G,B
Total Exposure time : 13 hours
Image capturing through CCDSOFT and TheSky6
Image processing entirely done in Pixinsight 1.7.
PIXINSIGHT PROCESSING
Calibration : save calibrated files in 16 bit, then for STL11000M use CCDOPS to fix vertical bars. 32 pixel for 1x1 binning
Register : save in 32 bit floating point
Step 1 Luminance processing, image integration, dynamic crop, DBE
Deconvolution:
-Luminance frame= linear , cropped edges
-DynamicPSF on 20 stars or so, extract mean PSF fits image
-Copy Luminance , HST to make a mask for protecting background during deconvolution. Make starMask.
-Deconvolution Gaussian PSF=external psf generated by DynamicPSF, Regularized richardson-Lucy, 100 iterations, Deringing support on with Global dark =0.04 and local deringing support by star_mask file and local amount = 0.7
Use copy luminance HST frame as mask to the linear image to be deconvoluted.
optional :Wavelet Regularization , 2 layers , Noise threshold =3.5 noise reduction 1 and 2 layer Noise threshold =2 noise reduction 1
MultiscaleMedianTransform MMT noise reduction image
-Linear Lum fits image, add inverted luminance mask, mask is HST stretched by transferring auto ScreenTransferFunction.
-MMT 5 layer
layer 1 Scale 1 S(t=2,s=1,a=1.2)
layer 2 Scale 2 S(t=0.5,s=1,a=0.5)
layer 3 Scale 4 S(t=0.5,s=1,a=0)
layer 4 Scale 8 S(t=0.3,s=0.8,a=0)
layer 5 Scale 16 S(t=0.25,s=0.8,a=0)
layer R scale 32
-MMT Sharpening, luminance mask
layer 2 scale 2 Bias +0.1
layer 3 scale 4 Bias +0.1
-HST stretched by transferring auto ScreenTransferFunction and take blackpoint HST to bottom of curve , not clipping background.
-Star reduction : Morphological transformation,size 3, iteraton 7, amount 0.15,selection 0.2, 2 ways 1 Circular 2 Diamond, use star mask on image
-HST adjust the blackpoint
Step 2 RGB processing , Dynamic crop on each R,G,B, DBE on each R,G,B
- R, G , B combine channels, global button
- Color calibration : White reference image Lower limit = 0.027 , output white ref mask, Background reference image upper limit= 0.04, output background ref mask, no structure detection
- MMT
- HST
Histogram black point HST
-Color Boost : luminance mask +curvestransformation on saturation
-SCNR green , amount 1 with inverted luminance mask
-RGB + inverted Extracted Luminance, use AssistedColorCalibration, R=1 G=1 B=1.2
-Star align RGB to luminance as reference
Step 3 LRGB combine
-Dynamic registration of RGB to Lum
-LinearFit Lum to RGB extracted Lum
-Lum combine to RGB , transfer function Saturation default
-HDRMultiscaleTransform
HDRMT 8 layers 3 to 5 iterations inverted Median Transform on, Lightness mask + Luminance checked , inverted starmask on luminance
-final HST
Hope you like it.
Wolfgang
www.vstobservatory.net
