PUNCH News

PUNCH is doing something very ambitious: merging together images from four separate instruments mounted on four separate spacecraft. Doing so requires very, very precise determination of the conversion between each pixel’s value and brightness on the night sky. That’s because, in one 90-minute orbit, the same feature on the sky is imaged by at least eight different pixels across different regions of at least three different cameras. Combining those data requires us to know exactly how to convert the value of each pixel to brightness on the sky.

During this meeting, we will track a CME through PUNCH's field of view and connect it to other mission observations.

We invite the community to attend the seventh PUNCH (Polarimeter to UNify the Corona and Heliosphere) Science Meeting from May 12th through the 14th, 2026 in Boulder, Colorado. As of May 2025, PUNCH has been taking observations, and everyone is invited to share their early results from these data. Topical science sessions will be organized around the themes of the origin and evolution of the ambient solar wind and turbulence within it and the physics, tracking, and predictability of transient events including CMEs, CIRs, and shocks.

PUNCH compresses its images on-orbit with “square-root coding”, to avoid downlinking photo-counting noise (Nugget #13 “Don’t Downlink Quantum Noise”). Removing the photon noise affects the statistics of remaining noise in the data, in a way that depends on the original data value. That, in turn, affects measurements of stray light in the instruments, putting a faint pattern of stripes in PUNCH photometric data (visible as the “stairstep” pattern in the blue trace in the top plot).

Last week, astronomers announced a new comet, designated C/2025 R2 (SWAN), that was discovered in Lyman-α images from the SOHO spacecraft. Since mid-August, PUNCH has been observing this comet, along with every other object within 45° of the Sun. PUNCH collects data at a 4-minute cadence in polarized light and at an 8-minute cadence in unpolarized light.

Energetic particles associated with shocks driven by fast coronal mass ejections (CMEs) or shocks developed by stream interaction regions (SIRs) often extend to high energies and are key elements of space weather. PUNCH is designed to track of solar wind structures through interplanetary space. Dayeh et al. (2025) reported a strong and robust relation between the shock speed jump magnitude at CME and SIR shocks, and the peak fluxes of energetic particles. Their analysis was based on 59 CME-driven shocks and 74 CIRs observed by Wind/STEP between 1997 – 2023. With that relationship, QuickPUNCH image sequences, and new methods for identifying speed jumps in the solar wind, we can forecast shock-associated particle events and their location in interplanetary space. PUNCH science data may become a crucial input to forecasting radiation events in the inner heliosphere.

The AIAA Small Satellite conference nominated PUNCH as a finalist for its prestigious Smallsat Mission of the Year award!