The MATISSE news page is separated into two parts. First a 'timeline of instrument status' is outllined, together with a table that lists important changes to the instrument status (this is formally complete from 13/09/20). Then, an 'announcements' section includes items regarding future changes to the instrument status. (This later section also includes instrument status changes prior to 13/09/20 that have not been incorporated into the table.) In the 'announcements' important information about the call for proposal are also listed.

Timeline of instrument status

The following table describes the events affecting the quality or the measurement of data obtained with MATISSE. Its content can be downloaded as a Comma Separated Values file. It is complete as of September 13th, 2020.

The Start Date column indicates when the event took place. Some events cannot be defined by a single instant, but extend over sometimes several days, weeks or months. Operation with the instrument may continue while the event occurs, in which case the Ongoing flag is set. If the event had ended, the Ongoing ? flag is lowered and End Date is given. The Type column indicates the characteristic(s) of the event: Earthquake, Maintenance, Upgrade, Element failure, Intervention, Pipeline installation at QC, Change of nominal values or thresholds, Modification of configuration file of this database, or Other. The Instrument Modes column indicates the affected mode. The column KPI indicates which quality control parameters identified as Key Performance Indicators (i.e., parameters following the most critical quantities) are affected; the column non-KPI indicates which other critical Quality Control parameters are affected. The Calibration Raw Types column indicates the raw types of the affected calibrations. The Calibration Breakpoint flag indicates if calibrations obtained before the event cannot be used for science data obtained after the event or if calibration data obtained after the event cannot be used with science data obtained before the event. The Comment column provides more details. The History column allows one to see possible past information on the entry.

The Quality Control pages for MATISSE can be accessed through the QC overview page

Announcements

October 2024: We would like to inform you of a problem recently identified with MATISSE N-band data recorded between May 16 and August 12. This problem resulted from a software update and went undetected at the time. Specifically, there is a mismatch between the actual chopping states in the N-band chopped data versus how the frames are tagged as sky or target. As a result, these data cannot be processed by the data reduction software. While an investigation is ongoing, it is highly unlikely that the affected data will be recoverable. Consequently, the data have been reclassified to Category C. The USD department will be in touch with the affected Principal Investigators in the coming days to provide further information.

December 2023: The final report on GRA4MAT performance indicated that fringe-jumps, causing loss of signal and hence reducing the SNR, occur much more frequently at higher water vapour content of the atmosphere. To avoid this, is recommended to observe with GRA4MAT at or below 5mm of precipitable water vapor (PWV) in the line of sight.

December 2023:  An issue in the pipeline originating in the different optical geometry of the two spectrometers was fixed, and a new pipeline version 2.0.0 was released. The problem resulted in a wrong sign of the phases, including closiure phase, in the N-band, causing an image or model rotation of 180 degrees. The issue was only present for the N-band, the LM-band image orientation was unaffected. This was confirmed by observations of a known double star. A preliminary investigation of publications, as of today, has not turned up yet any affected by this issue. The new pipeline version is available for download. Please visit https://support.eso.org and submit a helpdesk ticket to the User Support Department (Help topic: "Post-Observation", sub-topic: "Data Analysis and Processing", Subject "MATISSE pipeline") for any questions or concerns you may have.

Period 112: After completion of all commissioning runs and full evaluation of the available data, the sensitivity limits have been updated to their final values for MATISSE standalone, including a community supported correlated flux mode. Note, however, that the extended AT configuration has about 30% lower sensitivity limits due to additional reflections in the optical path.

Period 112: GRA4MAT is offered in a new narrow-field off-axis mode, in which GRAVITY tracks the fringes on a source, while MATISSE points to a nearby offset location in order to record fringes. This is useful for instance for planets or brown dwarf companions to brighter stars, if the offset positions are well known. Data from the commissioning of this mode is available for β Pictoris and a calibrator.

Period 109: GRA4MAT is offered for the first time on the UTs for measurements in the N-band without chopping.

June 2021: GRA4MAT mode is again available to the community in LOW spectral resolution only and on the ATs.

Period 108: MATISSE is offered in P108 (pending the successfull intervention scheduled in P107) both in stand-alone and in the GRA4MAT mode. All the spectral resolutions are allowed, with the caveat that the HIGH+ is offered only in GRA4MAT mode. In P108 MATISSE/GRA4MAT is offered for the first time on the ATs with chopping, meaning that absolute visibilities can be obtained. The GRA4MAT mode has to be chosen already at phase 1 using the dedicated acquisition. The most up-to-date magnitude limits and execution times to be used in P108 proposals are published in the Instrument Description page and in the Overheads page respectively.

February 2021: MATISSE has been experiencing problems with moving the grating LM-band wheel over 2020. The global health crisis prevented an intervention so far, and the situation degraded to the point where the wheel had to be put to a fixed position in January 2021. The *LOW position* was chosen with view on the statistics of the requested setups for the instrument, until an intervention takes place. Since the standard setup procedures, such as alignment and fringe search, require actuating the L-band grating wheel, new procedures have been worked out, partly using the N-band instead. The PIs of runs affected have been contacted by USD. Updates will be published on this webpage.

December 2020: after a long (forced) sleep MATISSE is back on sky on Dec 13 2020! The date marks also 100 years from the first measurements of Betelgeuse diameter by Michelson and MATISSE celebrated its return observing exactly the same source (Consortium press-release).

Aug 2020: we report a recently discovered bias introduced by the piston correction for MATISSE stand-alone N-band measurements, which may affect observations of faint sources (N bands fluxes fainter than about 6-8 Jy at 8 and 11 micron respectively). We remind that the offered limit for service mode N-band observations remains at 10 Jy. An investigation of such bias is currently undergoing. Updates will be announced in the current section.

A new version of the User and the Template Manuals have been released. They can be found in the Manual section from the menu on the left. The User and Template Manual, as well as the MATISSE webpages, are essential to prepare the phase 2 of the observations.

May 2020: a new version of the data reduction pipeline (vers. 1.5.1) has been released. We strongly advice to reduce the data with the current version. The pipeline can be downloaded at the following link . For any help with installation and usage of the pipeline, please contact USD.

March 2020: MATISSE  was shutdown as a consequence of the observatory being place in "safe state".  

Period 106: MATISSE is offered in both service and visitor mode on all the standard ATs and UTs configurations. Following succesfull commissioning, MATISSE is offered for the first time in P106 with GRAVITY as a fringe tracker (GRA4MAT mode). Among the possible spectral resolution available with the GRA4MAT mode, we also include for the very first time the HIGH+ spectral resolution in L and M-band. Please note: the turbulence categories for the GRA4MAT and for MATISSE stand-alone mode are different. The execution time of GRA4MAT concatenations is different from the one of MATISSE stand-alone. The details of the mode, and the limiting magnitudes are provided in the Instrument Description page. 

February 2020: open call for GRA4MAT mode Science verification. Deadline February 24th.

January 2020: a new version of the User and the Template Manuals have been released. They can be found in the Manual section from the menu on the left. The User and Template Manual, as well as the MATISSE webpages, are essential to prepare the phase 2 of the observations.

Period 105: during P105 MATISSE is offered in both service and visitor mode on all the standard ATs and UTs configurations. The following changes apply with respect to the previous call for proposal; the details are listed in the Instrument Description page.

• The L-band limiting magnitudes have been updated, and the M-band medium and low resolution are now offered after succesfull commissioning. 
• Due to additional commissioning scheduled during P105, that may lead to a revision of the instrument performances in M-band, the M-band medium resolution is not offered for monitoring programs.
• The medium resolution L- and M-band modes, as well as the high resolution L-band are offered for specific spectral windows centered around spectral features of interest. Additional set-ups are available in visitor mode. The spectral windows available in service mode are listed in the Instrument Description page.

Following the introduction of the new phase 1 proposal preparation and submission tool, the following important changes apply to all the VLTI instruments.

• A new atmospheric turbulence constraint replaces the current seeing constraint.
• The way the requested VLTI baselines and VLTI observation types have to be specified has changed. From P105 on, alternative baseline configuration can be specified at P1 in a keyword list, in order of priority. Note that each run will be scheduled on one configuration. Most likely, it will be the first (primary) choice. However, a run may exceptionally be scheduled on an alternative choice if the primary choice of the baseline configuration cannot be scheduled. All set-ups of each run need to specify exactly the same baseline configuration. If different configurations are needed, different runs need to be specified, each with one configuration.

August 2018: The decision to offer MATISSE in ESO period 103 was made.  MATISSE will be offered for both service and visitor mode observing.  Due to the still ongoing commissioning, that may lead to revision of instrument capabilities and performances,MATISSE will not be offered for Large Programmes or Monitoring Programmes in P103.

MATISSE in the news

For the latest highlighted science results, please consult the ESO Press Release page.