EUI Data Release 3.0 2021-07
DOI: https://doi.org/10.24414/k1xz-ae04
"EUI Data Release 3.0 2021-07", released on 2021-07-06 contains the Solar Orbiter/EUI L1, L2 and L3 data for the period 2020-03-03 up till and including 2021-04-28
This period covers the Near Earth Commissioning Phase (NECP) and the first 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.
Data policy, citation & acknowledgements
The "EUI Data Release 3.0 2021-07" 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.
Scientific papers using EUI data are asked to
- cite the EUI instrument paper "Rochus et al, AA, 2020".
- cite the above DOI to identify which EUI Data Release was used
- mention in the acknowledgements "Solar Orbiter is a space mission of international collaboration between ESA and NASA, operated by ESA. The EUI instrument was built by CSL, IAS, MPS, MSSL/UCL, PMOD/WRC, ROB, LCF/IO with funding from the Belgian Federal Science Policy Office (BELSPO/PRODEX PEA 4000112292); the Centre National d’Etudes Spatiales (CNES); the UK Space Agency (UKSA); the Bundesministerium für Wirtschaft und Energie (BMWi) through the Deutsches Zentrum für Luft- und Raumfahrt (DLR); and the Swiss Space Office (SSO)."
- send a notice to eui@sidc.be as to facilitate cross-referencing and accumulate statistics for future mission and team reviews.
The usage of EUI images as online web graphics or in printed materials should mention "Image Courtesy: ESA/Solar Orbiter/EUI".
List of changes as compared to EUI Data Release 2.0
- Data from 2020-03-03 till 2021-04-28 has been included
- FITS keyword IMG_TYPE = 'occulted image' for FSI images with the internal door in occulting position (and external door open).
- For combined gain images, the FITS keyword COMP_RAT now gives the compression ratio with respect to a 15-bit raw image of the same dimensions (was 12-bit for all images).
- Improved matching of FITS keywords OBS_MODE, OBS_TYPE, OBS_ID to observations defined in SOOP kitchen.
- The FITS keywords SOLAR_P0, SOLAR_PE contained incorrect values in previous releases, this has been fixed.
- To improve the accuracy of the FITS keywords GAINHG, GAINLG, OFFSETHG, OFFSETLG, their values are now extracted from parameter table dump reports instead of from housekeeping data.
- The last 32 columns of the FSI detector have been systematically removed from L2 and L3 images as these columns are not functioning correctly.
- The calibration software (euiprep) has been updated at various locations without altering the functionality. Minor changes in the L2 files are possible.
List of changes as compared to EUI Data Release 1
- Data from 2020-11-01 till 2021-02-18 has been included
- L3 data is included
- Added FILCPOS keyword. This is the commanded filter wheel position (FILTPOS is the actual filter wheel position determined from service 5 messages)
- Fixed unknown internal door status (DOORPOS=255), DOORINT is now determined from service 5 messages.
- Fixed OBS_MODE and related keywords. Now correctly taking into account the modules defined in SOOP kitchen: EUV, LYA, FSI, COMMON_MODULE (so it excludes matches with flushes).
- Fixed OBS_MODE and related keywords. If images are outside of observation period as defined in SOOP kitchen, then closest observation period in time is found (as sometimes we are imaging slightly before an observation period, while those images belong to that same campaign).
- Fixed values of HEEX_OBS,HEEY_OBS,HEEZ_OBS, and GSEX_OBS,GSEY_OBS,GSEZ_OBS after mistake was corrected in SPICE kernels.
- Fixed FSI plate-scale in L1 (CDELT1 was incorrectly set to 4.43614 in previous release, it is now 4.4353411)
- The calibration software (euiprep) has been continuously updated at various locations without altering the functionality. Minor changes in the L2 files are possible. For this release, the git SHA (first 8 characters) is 64ce9853 (see also FITS header VERS_CAL keyword).
- Updated FILTER keyword for FSI files; the values Magnesium_304_n26, Zirconium_174_n25, Magnesium_304_n4, and Zirconium_174_n13 are now used to identify the four available filters. (blocking positions are still identified by the value blocked, and any other position has the keyword value undetermined.
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 euiprep 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 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 64ce9853 (see also FITS header VERS_CAL keyword).
The eui_prep routine is only applied to lossless compressed or uncompressed Level-1 solar images, starting with the 'first light' images on May 12, 2020. Technical images such as e.g. 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 an extra 20 images have been added to the Level 2 release with IMGTYPE="unknown image", that correspond to 'occulted images' (see known issues below).
For this release, a total of 14882 images have been selected and processed.
The L2 file version number is incremented every time the L2 file is updated and may thus differ from the L1 file version number.
Level 3 data
Level 3 data corresponds to a further processing of Level 2 data for visualisation purposes. The Level 3 image files are intended for visualisation through JHelioviewer.
This release contains 14882 L3 files.
Known remaining issues
- Spacecraft pointing instabilities (thermoelastic, others) might affect the pointing metadata. It is recommended to use the pointing metadata only as a rough approximation. For FSI L2 images, the pointing metadata was updated using a solar limb-fitting procedure, and should typically be more accurate than 0.5 pixel for FSI174 images, unless the solar limb is saturated in the image. Limb-fitting is not fully satisfactory yet in about half of the FSI304 images. This will be revisited in future releases.
- CMOS sensor settings vary a lot throughout NECP. Various CMOS issues (image lag, unstable offset) are still being addressed at the time of writing. EUI images are not suitable for photometry yet.
- FITS files containing 'wicom2' in the filename contain broken images. The meta-data inside these files is correct, but the image data itself could not be decompressed properly and should be considered lost.
- the calibration of the detector temperature sensor is to be improved. The temperature keywords (TEMPINT, TEMP1DET, TEMP2DET) can deviate.
- For HRILYA, LYCMCP and LYCSCR FITS keyword values are inaccurate for low values.
- Certain L2 files contain NaN values in one or more columns. In L3 files, these NaN values show up as bright lines.