The Tulip Nebula (Sh2-101) in the constellation Cygnus (the Swan)

Moving from Siril to PixInsight to process my astro images

Acquired close to six hours of data on the Tulip Nebula.  The image above was processed using PixInsight with the BlurXterminator and NoiseXterminator plugins along with StarReduction.  

The light frames were captured using an OSC rig, consisting of a Redcat 51 telescope, asi183mc pro cooled color astronomy camera and an l-extreme dual narrowband filter.  I also autoguided in order to obtain 180 second subs.   It was a good night of seeing, clear skies with camera cooled to -10C.  

Prior to processing, I stacked the light frames using Deep Sky Stacker along with about 10 dark frames.  

The image below was processed using the free Siril Application.  On the surface both images appear to be not too far off from one another as far as quality.  It is when you zoom in on details that you can see the reason why serious astro imagers are willing to pay to use PixInsight.  

The stars are much more sharp and natural in appearance in the PixInsight image.  There is much finer detail in the nebula, particularly the dark structures and the colors and contrast are much more refined.  In addition to this the PixInsight image is less noisy than the one processed in Siril.   I had been imaging for over a year using just Siril and Gimp alone because it allowed me to get nice results without having to pay for software.  But after looking at images on Astrobin more closely I began to see how most of the finest looking images were processed in PixInsight.  Considering how much is spent on hardware to get the best results possible, the expense of PixInsight along with the plugins is not really that much, especially if you want to get the best out of your astro gear as a whole.  

I initially stayed away from PixInsight not only because of the cost, but what I perceived to be a large learning curve.  However, having gained much experience with Siril and watching a few videos on PixInsight I decided to download the trial and was able to get productive in using in a very short period of time.

A monochrome camera version in SHO

7 hours 15 minutes of data

9 hours 20 minutes

PixInsight Processing Steps:

Linear Fit

Channel Combination (S as reference)

Dynamic Background Extractor

BlurXTerminator

Screen Transfer Function/Histogram Transformation

Starnet2

SCNR Green Removal 24%

Luminance Mask (invert)

Curves Transformation, darken background

Mask Invert

Curves Transformation, reduce green

Further adjust to liking, Curves Transformation, colors, saturation, background

NoiseXTerminator

DarkStructureEnhance

Duplicate Image04

CorrectMagentaStars on star mask

PixelMath combination

StarReduction

Save

Further adjustments in Mac Preview, colors and sharpening

Processed using new color mask generation tools

Much better control over colors