Here is a more thorough process of the Eastern Veil shot earlier this month. It soon became clear that more data is required for a truly clean result – as once I I had removed subs ruined by guider errors and clouds I was only left with as few as 4 OIII subs for the head of the nebula and consequently there is more noise than I would like.
This time I wanted to see how PixInsight handles mosaic construction.
Building a mosaic with photoshop is pretty straight forward: select the pictures you want and click photomerge – Done. With PixInsight video tutorials are necessary with 2 steps to follow:
First us the Star Alignment tool with Working mode set to RegisterUnion Separate and Frame Adaption ticked. The resulting registered images need to be saved
Second Use the GradientMergeMosaic tool to open the saved images and set the Combination type to Overlay.
My quick comparisons so far have shown that whilst Photoshop can make a good fist of this PixInsight’s specialist tools create a superior result for astro images. This is especially true for images with relatively small degrees of overlap – where Photoshop often fails to align the images.
The processing took a couple of goes to stop the join being obvious as I found it tricky to remove the gradients. The most successful approach was to create mosaics of each colour channel before combining to LRGB.