A reduced-resolution NFI YouTube movie reveals CMEs, solar wind flow, comets, and constellations over the first full year of science operations of the PUNCH mission. Full resolution photometric NFI data are included in the September 2026 v0m data release, realizing the full field of view of the PUNCH mission (from 6 to 180 solar radii).
Recent image processing developments at the PUNCH Science Operations Center (SOC) have enabled recovery of photometric data from the Narrow Field Imager (NFI) coronagraph. NFI is has been accumulating data throughout the mission, along with the more familiar Wide Field Imager mosaics, but is so strongly affected by bright, variable stray light that it has been omitted from the PUNCH mosaic data released in Versions 0a through 0l of the PUNCH preliminary data products. For the first time, Version 0m, in the process of being released, will include NFI photometric data in the mosaics.
The SOC team recently released an overview of the NFI dataset as a movie that shows CMEs, variable coronal structure, the starfield, and even several comets over the course of the first full year of mission operations.
Removing the stray light pattern required treating each image as a vector in a 4-million-dimensional space. The stray light occupies a small corner of this space. Because the camera systems (made by RAL Space and Teledyne) are extremely linear, it is in principle possible to identify precisely that corner and zero it out, while preserving the corona. Identifying the precise locus of the stray light is challenging. We now use a technique called "Principal Component Analysis" (PCA) to examine swaths of NFI images a few days at a time and identify an approximation of the stray light. The output will continue improve version to version as the SOC refines the method, but NFI data are now sufficiently refined to be useful in conjunction with the wider-field WFI mosaics.
This is PUNCH Science Nugget #40. PUNCH nuggets are archived at https://punch.space.swri.edu/punch_news_archive.php. You can subscribe to PUNCH nuggets by email: https://forms.gle/XVNjURj2izVzMrct8.
