Twenty-five 5-minute light frames, calibrated, registered, stacked, and post-processed using PixInsight. I was having a bit of trouble before this shot, my stars had colour fringes caused by the coma corrector. I have started performing my collimation with the coma corrector in place, which seems to have reduced this problem significantly. I think it’s just because the coma corrector isn’t as snug a fit as it should be in the focuser tube.
- Date taken: 27/11/2014
- Location: Adelaide, South Australia
- Camera: Canon 450d w/ IR filter removed, GSO coma corrector
- Mount: HEQ5PRO
- Scope: GSO 8″ f/5 Newtonian
- Autoguider: Orion Starshoot AG
- Imaging: BackyardEOS w/ PHD dithering
- Guiding: PHD2
- 50 bias frames, 20 dark frames, 50 flat frames.
- Total integration time: 125 minutes
- BatchPreProcessing, calibration only
- Star Alignment
- Image integration (using Winsorized Sigma Clipping)
- Dynamic Background extraction, twice, first time to remove the majority of the light pollution, then a second run to reduce some of the gradients from nearby light sources.
- Dynamic Crop to remove some of the dodgy edges, also centering the image on NGC1365
- Extracted luminance from the RGB for later on
Processing the RGB Image:
- ATrousWaveletTransform to reduce noise
- HistogramTransformation to reveal the galaxy etc
- ACDNR to further improve noise
- ATrousWaveletTransform a few more times with various masks to reduce noise and even out the background
- Blurred the RGB image with ATrousWaveletTransform by removing all the detail from the first 4 layers!
Processing the luminance image:
- Much the same as before, ATrousWaveletTransform to reduce noise
- HistogramTransformation to stretch the image
- More ATrousWaveletTransform, this time using a mask generated from a cloned image, HistogramTransformation used to auto clip highlights & shadows
- Same mask, ACDNR.
- Bit more HistogramTransformation now that there is a lot less noise
- Pixel math: star_mask+range_mask, masking everything but the stars and galaxy
- LocalHistogramEqualization to bring out some more detail in the galaxy
- Tiny bit of bias in ATrousWaveletTransform to sharpen up the galaxy
Putting the images together:
- Saturation increased a tad, 0.350 or so, but otherwise just applied L to RGB
- CurvesTransformation to tweak the saturation and luminance a tad, and increase contrast