This is a two panel Mosaic of the Lagoon nebula.   It is one of my favorite targets, and was my first project with my RiDK 400 rig in Chile.  It was already late in the season when I started, and this was my first light on this telescope so there were some challenges with the data for sure.  The target was low on the horizon, seeing was poor and I was still tuning the rig.

Once I finally came around to processing the data, I realized that I had completely forgotten to capture blue data for the stars!  It was already too late and the target was gone for the year.  However, at the same time that I was collecting this data, I was also collecting data on my FSQ106 for a wide field view.  So I had good RGB data from that project, although at 380mm focal length vs 2800mm on the RiDK. 

I thought that it would be a fun challenge to figure out how to use the FSQ data for stars.  Here is how I did it. 

I first processed a set of the NB data focusing on the star shape and luminance.  Star shapes through the narrow band filters are nicer anyway, in my opinion.  I then extracted the stars from the image, then extracted the luminance layer from the star image and put it aside for later.

I cropped the area of interest out of the processed FSQ wide field RGB data.  Since the tiny FSQ stars were under-sampled, I resampled the data by 2x.  I played with the different methods and settled on nearest neighbor.  I applied a light convolution to the resulting star image to average the few resampling artifacts into the stars.

I then aligned that image with the NB lum layer that I had extracted earlier, and finally applied that luminance layer to the engineered RGB stars layer to end up with proper RGB stars.  This was later added the the final starless NB image.  The result was pretty spot on I think!  I may actually explore this NB stars lum method going forward.

My goal in processing was to go for a natural color pallet focused on reds and blues using my RGB data as a guide.  For most targets, I struggle with using the traditional NB SHO pallet with its mustard yellows.  So I do tend to stray from traditional NB color pallets, even though I sense this may cause some form of disadvantage in the IOTD process.   I try to approach each project with an artistic eye first though.

I am also trying to consciously reduce my urge to sharpen.  I am fortunate enough to be starting with great data and I think I tend to over do it.   This image has very little sharpening applied.

Hope you like it.

CS