The Mosaic By Coordinates script in PixInsight is a tool for creating mosaics of astronomical images. It works by using the coordinate information embedded within the FITS header of each image file to align them. These coordinates are determined by using the Image Solver script within PixInsight.
Because we added the right ascension and declination coordinates to the FITS headers with the PixInsight Image Solver script, aligning our images is extremely easy.
Unsure of the mosaic processing order? Use the Mosaic Workflow for Astrophotos
Mosaic by Coordinates
When the mosaic panels are ready, simply launch the Mosaic by Coordinates script (Scripts – Mosaic – Mosaic by Coordinates):
- Files: Add the mosaic panels
- Output: Select an output directory
- Projection: Select the Projection model used for the Image Solver script. For mosaic, this is typically the Stereographic projection model.
Once configured, select OK.
Interpolation
The Mosaic by Coordinates script incorporates many types of interpolation methods. Interpolation offers a way to improve the smoothness and potentially reduce artifacts in the final mosaic image
Use Lanczos when:
- You prioritize preserving sharp edges and details in the image.
- Ringing artifacts are less of a concern.
Use Bicubic Spline when:
- You prefer a smoother overall image appearance.
- Slight softening of details is acceptable.
However, in the current image, the differences are almost imperceptible. The image has been significantly zoomed to try and see the difference.
By looking really close, one can make out that using the Lanczos-3 method produces slightly smaller stars, yielding a crisper image when compared to Bicubic-Spline.
What’s Next
Now that the images are aligned, we need to have the brightness adjusted so they will merge together seamlessly. This is done with DNA Linear Fit.