PUNCH News & Nuggets

Late November through late January is the darkest time of year in Earth’s northern hemisphere, as Earth’s axis points away from the Sun, making nights longer and days shorter. PUNCH experiences the seasons too: during these dark days, each spacecraft spends a few minutes per orbit passing through Earth’s shadow (and experiencing a brief “night”). This plot shows the state of charge of all four satellites’ batteries over the ten-week “eclipse season”, highlighting that even orbiting spacecraft experience the same astronomical calendar that we do.

final integration and testing on the Narrow Field Imager (NFI) in a cleanroom facility. The red hardware components are protective covers that were removed before flight. Detailed diagram showing the compact design of the Narrow Field Imager (NFI). The cut-away view illustrates the internal components, including baffles, heat rejection mirror, and the optical lens assembly which are all configured to image the faint light of the corona to the camera. The Narrow Field Imager (NFI), the coronagraph for NASA's PUNCH mission, images the innermost part of the PUNCH field of view. It was delivered about eight months before launch, and successfully met all pre-launch requirements in testing. NFI is an example of a new class of “compact” coronagraphs developed at the Naval Research Laboratory, with a single stage of external occultation to observe the faint solar corona with a small form factor.

PUNCH CONNECT (COmmunity Nexus for Noteworthy Event Context and Tracking) is a new topical focus group open to the community, dedicated to identifying solar and heliophysical events that benefit from cross-mission activities.

(photo credit: PUNCH Outreach - D. Johnson, C. Morrow, D. Cornucopia) PUNCH mission's “first light” released on June 3rd. The PUNCH Outreach team has contributed to cultural astronomy research in Chaco Canyon, NM by determining the two dates (before and after summer solstice) when the “first light” of sunrise occurs with a dramatic “double diamond ring” effect atop a horizon feature called Triangle Rock. On these dates, the apex of Triangle Rock's shadow passes through the center of a large spiral petroglyph on the eastern face of an Ancestral Puebloan solar observation site called Rock of the Sun. The spiral center defines the viewpoint for the sunrise “horizon calendar” that features the double diamond spectacle and other visually prominent interactions useful for tracking time near the summer solstice.

Each PUNCH instrument uses three polarizers, aligned 60° apart, to measure how much, and in which direction, light from the sky is polarized. We can then display the images using color to represent the polarization of the light.

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.