EUI Data Release 1

Release date

Release Notes & Disclaimer

EUI data release 1 contains the Solar Orbiter/EUI data recorded up till October 30. This period covers the Near Earth Commissioning Phase (NECP) and the first few months of Cruise Phase. This implies that most data is the result of technical tests, for which the instrument configuration was often non-nominal. Most data is therefore a-priori not suitable for scientific analysis but is instead primarily intended as a reference for the further development of analysis and visualisation software.

Level 1 data

Level 1 data implies that the metadata in the FITS keywords is complete but that the images remain uncalibrated. Besides decompression, only limited, reversible operations have been applied to the images (mirroring & flipping, and 90-degree rotations) such that solar north is roughly on top and solar east roughly on the left. All the images received on the ground are distributed in the Level 1 dataset. This includes many images with the telescope doors still closed, either darks or LEDs (calibration lamp images). The first of these were received on March 3, 2020.

Level 2 data

The eui_prep python routine takes the Level 1 data and rectifies instrument deviations for which corrections are available. It also updates the WCS FITS keywords to correct for spacecraft pointing instabilities. The output of these calibration steps is distributed as Level 2 data. The eui_prep routine is in an early development phase and in continuous evolution. The Level 2 data are thus a snapshot of the best available corrections at the time of the Level 2 data production.

The eui_prep routine is only applied to Level-1 solar images, starting with the first light images on May 12, 2020. Techincal images such as darks or LEDs are not processed into Level-2 data. The selection is done with the IMGTYPE keyword which is set to IMGTYPE=solar image if * both the heat shield doors and instrument doors are open, AND * no LED is on AND * if the telescope has a filter wheel, that this filter is not in a blocking position.

For HRILYA, extra conditions are added to make sure the Screen and MCP voltages were properly configured for solar imaging. For HRILYA images with exposure time less or equal than 3s (XPOSURE LE 3.0) we require

LYACSCR > 3450 AND ((GAINCOMB="low-only" AND LYACMCP> 580) OR (GAINCOMB="high-only" AND LYACMCP> 450))

For HRILYA images with exposure time larger than 3s (XPOSURE GT 3.0) we require

LYACSCR > 3450 AND ((GAINCOMB="low-only" AND LYACMCP> 480) OR (GAINCOMB="high-only" AND LYACMCP> 350))

For FSI extra images have been added to the Level 2 release with IMGTYPE=unknown image, that correspond to occulted images (see known issues below).

The git version number of the euiprep S/W used to generate these L2 files is copied in the FITS header HISTORY keyword. For this release, the git SHA (first 8 characters) is f7cd7fca except for the HRI-LYA images of October 2020 that were generated using git SHA-1 a15a64ad.

Data policy

The EUI data releases 1.0 is public and can be freely downloaded from the EUI website and from the Solar Orbiter Archive.

Because of the technical and uncalibrated nature of the current release, it is strongly recommended to get in contact with an EUI Consortium member who will provide technical assistance during data handling. In return, co-authorship on eventual publications is expected. If you are not sure who to contact, ask a suggestion to the EUI Principal Investigator Team.

Citation & acknowledgements

Scientific papers using EUI data are asked to cite the EUI instrument paper Rochus et al, AA, 2020. The usage of EUI images as online web graphics or in printed materials should mention Image Courtesy: ESA/Solar Orbiter/EUI. The full EUI team (CSL, IAS, MPS, MSSL/UCL, PMOD/WRC, ROB, LCF/IO) can optionally be mentioned in acknowledgements.

Papers using EUI data are friendly requested to send a notice to as to facilitate cross-referencing and accumulate statistics for future mission and team reviews.

Known issues