The images show the Low-Latency (LL02) line-of-sight magnetic field (Blos) and the continuum intensity (Icnt) obtained by the Full Disk Telecope (FDT) of the Polarimetric and Helioseismic Imager onboard Solar Orbiter (SO/PHI). LL02 data are produced from onboard-processed, spectropolarimetric reconstructions of the Stokes profiles sampled at 6 points in the 617.3nm Fe-I absorption line and the nearby continuum. LL02 are primarily produced as a support for Solar Orbiter's high-resolution observation campaigns. However, given their unique value for space weather predictions, they are now produced on a daily base, compatibly with spacecraft operations.

Data Limitations

The LL are of lower quality than the regular SO/PHI science data in a number of aspects. First, the LL02 are only roughly flat- and dark-corrected. This may result in an imperfect calibration, and residual artifacts. An example of such residual artifacts is a dust grain that is often not properly removed: this can be easily recognized as a black/white speck a few pixel wide in the continuum image that has no correspondent magnetic field concentration. Second, the inversion method that we use onboard for the LL02 data is a center-of-gravity method rather than the Milne-Eddington inversion that we use for science-grade data. Third, some of the methods to remove optical artifacts that are available in the on-ground processing pipeline are not yet available onboard (fringes, ghost, and cavity map corrections). Last, the LL02 are often downlinked at high compression rates for telemetry reason, which increases the noise with respect to regular science data.

Data Usage

LL02 data are not of scientific quality and are provided in good faith by the SO/PHI team for use only in making real-time space weather predictions. More information on regular, level2 (L2), released science-grade PHI data can be found at https://www.mps.mpg.de/solar-physics/solar-orbiter-phi/data-releases.

Additional Information

For additional information on the SO/PHI instruments (the Full disk Telescope and the High Resolution Telescope), the available data, references, and acknowledgement policy, please refer to the SO/PHI web page https://www.mps.mpg.de/solar-physics/solar-orbiter-phi. Please, address any question on SO/PHI observations to sophi_support@mps.mpg.de

These images are reproduced for space weather purposes only. Original source of this data is from the EUI team at the Royal Observatory of Belgium/ SIDC. Please check the ESA/SOAR archive (linked to https://soar.esac.esa.int/soar/) for the latest processing of the EUI data.

The Solar Orbiter spacecraft carries the Extreme Ultraviolet Imager (EUI) which includes the Full Sun Imager (FSI). The FSI telescope monitors the Sun's hot outer atmosphere, namely the corona and the transition region. EUV photons are created in the hot plasma of the solar atmosphere and are not visible from the ground, due to the absorption of the Earth's atmosphere. Observations of solar EUV emission aids in the early detection of solar flares, coronal mass ejections (CMEs), and other phenomena that impact the geospace environment.

The EUI/FSI telescope follows Solar Orbiter in its variable orbit around the Sun meaning that its perspective is not always the same as for Earth-bound telescopes and sometimes the back-side of the Sun is imaged that is not visible from the Earth. The Solar Orbiter is highly elliptic with the closest approach to the Sun more than 3 times as close as the Sun-Earth distance. Since February 2025, Solar Orbiter is also progressively leaving the ecliptic plane meaning that FSI sometimes has a much more "polar" view of the Sun than the Earth.

FSI typically takes an image every few minutes in each of its wavelengths but the exact imaging cadence is variable to accommodate the variable telemetry availability along the orbit.

Available wavelength: 17.4 and 30.4 nm