SPICE Data Release 5.0
SPICE consortium
2024-09-16
DOI:10.48326/idoc.medoc.spice.5.0
Access to data:
This data pack contains Solar Orbiter/SPICE data recorded during:
- Cruise Phase: Short Term Planning periods (STP) 100 to 179. These
data were acquired early in the mission, under variable instrument
configurations.
- Nominal Mission Phase, from STP180.
We distribute both Level 2 (L2, calibrated) and Level 1 (L1,
uncalibrated) files. However, scientists should use L2 and not L1 files
for their research. L2 data take into account all the calibration
parameters quantified at the time of the release. L1 files are only
provided to investigate possible issues with the conversion from L1 to
L2. The conversion software will eventually be released in SolarSoft.
Users should contact the SPICE team in case they think they have a good
reason to use L1 files.
Citation and
acknowledgements
Scientific papers using SPICE data from this data release must:
- Cite the SPICE instrument paper “SPICE consortium et al, A&A,
2020 DOI:10.1051/0004-6361/201935574”;
- Cite this data release: DOI:10.48326/idoc.medoc.spice.5.0. This can
be done following the suggestions by DataCite;
- Include the following statement in the acknowledgements
section:
The development of SPICE has been funded by ESA member states and
ESA. It was built and is operated by a multi-national consortium of
research institutes supported by their respective funding agencies: STFC
RAL (UKSA, hardware lead), IAS (CNES, operations lead), GSFC (NASA), MPS
(DLR), PMOD/WRC (Swiss Space Office), SwRI (NASA), UiO (Norwegian Space
Agency).
The usage of SPICE images as online web graphics or in printed
materials must mention “Image Courtesy: ESA/Solar Orbiter/SPICE”.
Documentation
Known limitations
- The spatial resolution is lower than measured pre-flight: 5.4” from
ground tests, 6.7” in flight.
- The spectral resolution is lower than measured pre-flight: (a) 2”
slit, SW channel: ground test – 4.7 pixels, flight – 7.8 pixels; (b) 2”
slit, LW channel: ground test – 5.3 pixels, flight – 9.4 pixels.
- There is a systematic bias in measurements of Doppler velocities
correlated to the intensity gradients — an effect qualitatively similar
to what was reported in SoHO/CDS (Haugan 1999) and
Hinode/EIS (Young
et al. 2012; Warren et al. 2018),
although with a larger magnitude. The source of this bias appears to be
a combination of anisotropic PSFs (i.e., astigmatism) in both the
telescope and spectrometer sections. An effort is on-going to model the
effect and to devise corrective actions. As of today, we recommend not
to interpret Doppler velocities in SPICE data without contacting the
instrument team for advice. A deconvolution software is being developped
(Plowman
et al. 2023), the method is currently under test prior to
deployment.
- Some specific observations have been done during spacecraft “Wheel
Off-Loading” (WOL) events for testing purposes, then the pointing was
unstable. The correct pointing information is however present in the
WCSDVARR FITS file HDUs and the data can be rectified if
needed.
- Observations made during commissioning and cruise-phase were mostly
of engineering type and are therefore not all suitable for scientific
analysis. Caution is recommended when using these. STP134 for example is
unfit for scientific analysis.
- Files built from incomplete telemetry (with header
COMPLETE='I') are also unfit for scientific analysis.
Change log
New in Data Release 5.0
- L2, updated absolute calibration: compared to the
files from Data Release 4.0 the irradiances of Data Release 5.0 are a
factor 1.613 times higher for 2” slit observations and 2.016 times
higher for the 4”, 6”, and 30” slits.
- L2, dark subtraction: for observations around
perihelion the dark subtraction is obtained through the use of combined
darks. For other periods, the subtracted darks are files that have been
cleaned for cosmic rays. If no cleaned dark is available, a regular
untreated dark is subtracted, as in previous data releases.
- L2, burn-in correction: updated description of
burn-in, 2024-08-28. Compared to the previous data release, the
following lines have a modified burn-in definition:
- SW: N IV 76.51 nm, Ne VIII 77.04 nm
- LW: H Lyman γ 97.25 nm, C III 97.7 nm, H Lyman β 102.6 nm, O IV
103.9 nm
- L2, time dependent detector response: new response
table, 2024-08-08.
- L2, distortion correction: new distortion
correction matrix, 2024-07-04.
- L2, wavelength scale: new temperature dependent
wavelength scale
- L1 and L2, pointing:
- The spacecraft pointing is now corrected for the stellar aberration
effect. This is what is usually done on solar missions (the origin of
helioprojective coordinates is at apparent Sun center),
although it is inconsistent with the current SO
Metadata standard.
- Modified SPICE vs spacecraft offset correction.
- L1 and L2, bug fix: a bug that caused incorrect
intensities for spectrally binned windows that had an on-board pixel
level offset has been fixed.
- L2, removed engineering files: L1 files resulting
from an engineering study to set-up detectors for full frame read-out
(
STUDY_ID = 57) do not contain any science data. These
files are therefore no longer calibrated, meaning that 1704 L2 files of
Data Release 4.0 have no counterpart in this data release.
New in Data Release 4.0
- L2: The data have been corrected in some wavelength regions where
the detector sensitivity has decreased due to burn-in by strong emission
lines:
- SW: N IV 76.5 nm, Ne VIII 77.0 nm, Ne VIII 78.0 nm
- LW: C III 97.7 nm, H Lyman β 102.6 nm, O VI 103.2 nm
- L2: The data have been corrected for the time-dependent degradation
of the detector sensitivity.
- L2: Binary table extensions containing detailed information on
approximated and lost image planes due to lost telemetry have been
removed.
- L1 and L2: Several changes have been made to the metadata contents.
See the Data Product Description Document for details.
- Bugs that have been fixed:
- L1 and L2: Rasters:
CRVAL1 values was shifted to the
east by approximately one slit width.
- L1 and L2: All study types: Roll angle and
CRVALi were
set to mean of the values of all exposures instead of the values at
CRPRIXj.
- L1 and L2: Distortion correction arrays were multiplied by
-1
- L2: Some files produced after February 2023 had missing pixels not
being
NaN.
New in Data Release 3.0
- L1 and L2: Wide-slit observations are no longer reversed in the
wavelength dispersion dimension, i.e. Instrument-X is now increasing
with increasing wavelength pixel.
- L1 and L2: Temperature dependent SPICE vs spacecraft pointing offset
taken into account when calculating WCS keywords.
- L1 and L2: Information on pointing variations due to spacecraft
pointing instabilities during the observation is put in two separate
WCSDVARR image extensions (one per dimension).
- L2: Adjacent windows that are merged now occur only once in the FITS
file.
- L2: Binary table extensions containing detailed information on lost
telemetry have been removed.
- L1 and L2: Several changes to the metadata contents. See the Data
Product Description Document for details.