This section provides brief notes on observations that had observational or processing issues. This list is not exhaustive, and the user is always encouraged to examine the data and inspection plots closely.

Observations with no released processed data

Some observations have no released processed data associated with them. This can either be because they were processed with the 300 MHz version of the pipeline, which produced lower quality data products, or because the automatic identification of calibrators by AUTOCAL (see "Apercal overview") and subsequent processing failed. In addition, there is a set of observations that were scheduled without RTC & RTD, thus failing to be validated for release since they did not meet the minimum resolution requirement.


Early processing

The following observations have no released processed data products because they were processed with the 300 MHz version of the pipeline, which did not produce data products of the required quality.

ObsID Field
190711169  S2152+4114
190712041  M1403+5324
190713001  M0155+3130
190713042  S2323+2904
190714041 S1444+5058
190718124  S2146+4340
190719041 S1242+5058
190719042  M0155+3130
190720041  S2336+2904
190721041 S1426+5058
190722001 M0208+3130
190725041  S1236+6041
190725042  M0155+3130
190726041  S2319+3130
190727041  S1439+5324
190727042  M0208+3356

Table 1. Observations processed with 300 MHz version of pipeline.


Autocal failures

The following observations have no ingested processed data products because the automatic running of the pipeline failed in their case. Generally this was because of an issue with identifying calibrators. These observations can be manually reprocessed. Access to the raw data can be requested via the helpdesk.

ObsID Field FluxCal:


190728041 S2258+2904 3C147: 190727 001-040 3C286: 190728 001-040
190731125 S2227+3130 3C147: 190801  001-040* 3C286: 190731 085-124
190806345 S2311+2904 3C147: 190807 001 - 040 3C286: 190808 001-040
200429042 S1446+3848 3C147: 200429 002 - 041 3C138: 200428 001 - 040**

Table 2. Observations not processed due to failure of automatic calibration identification. Notes: *Observations 028-033 failed. **Go backwards for a pol cal that has C/D (see Obs fails below).


Observational failures

If RTC and RTD are unavailable, an observation is considered failed. Some of the early observations from July, which don’t have processed data available, may suffer from this as both RTC and RTD had issues with delay jumps (see System notes). In addition, there are a series of observations from April/May which were inadvertently scheduled without RTC and RTD and thus don’t have processed data which passes validation. These observations are:

ObsID Field
200430053 S1131+6041
200501001   S2346+5324
200501042 S2346+5324
200502054   S1142+5550
200503001  S2358+4832
200503042  S1443+3622
200505016 S0001+4606
200505057 S1446+3848

Table 3. Observations scheduled without RTC & RTD.

Partially processed observations

Calibrator identification issues

Two observations, 191207034 and 191207035, do not have processed data products for the first seven beams, as those beams (due to scheduling complications) were not properly identified by AUTOCAL. Given the small number of beams missing, they were not reprocessed. These observations can be manually reprocessed. Access to the raw data can be requested via the helpdesk

Reprocessed observations

Reprocessed with manual flags

As part of the data release, observations where essentially all beams failed validation (e.g., four or fewer beams passed) were visually inspected to identify the cause. In some cases there were no obvious causes, other than bright sources in the field. In other cases, inspection revealed an antenna was off-source (e.g., stuck) during the observation or part of the observation occurred while the target field was not visible. In order to increase the quality of the processed data from these fields, they were manually reprocessed with the additional, visually identified, flags applied. Other fields may also benefit from individual flags and reprocessing.

These observations are:

ObsID Field Note
191024043 S1402+3622 Flag RT2, plus first five minutes
191024044 M0155+3622 Flag RT2
191209025 M1342+2904 Flag RT9
191227014 M0155+3356 Flag RT9, plus ~15 minutes of RTA due to extra shadowing (by  stuck RT9)
191230041 S2300+3848 Flag RT9
191031242 M0155+3622 Flag first ten minutes
200305001 M0141+3622 Flag last 1h10min
200427042 S1427+3130 Flag RTB

Table 4. Observations manually reprocessed with additional flags.


Reprocessed with correct polarization calibrator

There were two observations where AUTOCAL incorrectly assigned the same flux calibrator to be both the flux and polarization calibrator to the initial call of Apercal. These observations were reprocessed with the correct polarization calibrator.

200126082 S1428+5815 3C147: 200126 042 - 081 3C286: 200126 001  - 040
200406054 S1611+5324 3C147: 200406 014 - 053 3C286: 200405002 - 612

Table 5. Observations manually reprocessed with correct polarization calibrator.

Data quality notes

Problems with polarization data

There is one dataset which has no polarized data products as a polarized calibrator was not able to be observed in the same observational setup. This is ObsID 200309042, field S1042+5324.

In addition, the observation 200505057 was processed without a polarization calibrator. However, since it has no released processed data due to missing RTC and RTD and thus failing resolution requirements, it was not reprocessed. These observations can be manually reprocessed. Access to the raw data can be requested via the helpdesk


Latest tweets

Daily image of the week

On June 13-17, the LOFAR Family Meeting took place in Cologne. After two years LOFAR researchers could finally meet in person again. The meeting brings together LOFAR users and researchers to share new scientific results.

Our renewed ‘Melkwegpad’ (Milky Way Path) is finished! The new signs have texts in Dutch on the one side and in English on the other side. The signs concerning planets have a small, 3D printed model of that planet in their centre.
#Melkwegpad @RTVDrenthe

Daily image of the week

The background drawing shows how the subband correlator calculates the array correlation matrix. In the upper left the 4 UniBoard2s we used. The two ACM plots in the picture show that the phase differences of the visibilities vary from 0 to 360 degrees.

Daily image of the week: Testing with the Dwingeloo Test Station (DTS)
One of the key specifications of LOFAR2.0 is measuring using the low- and the highband antenna at the same time. For this measurement we used 9 lowband antenna and 3 HBA tiles.