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DR3 Release - December 6th 2007

January 2011 - constituent reprocessed frames used to make the UDS deepstack in DR8 are available via the Archive Listing under the WFCAMOPENTIME database release. Only those frames taken on dates covered by DR3 are available.

Important note:

1) The Y zeropoint has been changed by 0.08 in the sense that Y(DR3)=Y(DR2)+0.08, i.e. objects are now fainter in Y. This is the most important calibration change since DR2.
2) DR3 was updated Jan 31st 2008 to include GPS data. (The initial release of DR3 did not contain GPS data).

NEW FEATURES IN DR3: There are several new features in this release. These include

  • Neighbour tables between the source tables containing deep object detections and the detection tables containing both deep catalogues and catalogues for each scheduled block of observation in the DXS and UDS. These tables are called dxsSourceXDetection and udsSourceXDetection. This allows users to look for variable objects and to quickly generate light curves.
  • The UDS now contains a H-band mosaic as well as J and K and it now also includes cross-talk flags.
  • There has been a significant recalibration of the photometric data, so that each detector in a frame has an independent zeropoint.
  • Source merging has been changed/enhanced as follows: the core pairing software has been improved; the GPS source table is reduced in width to exclude attributes from epochs that have not yet been observed; and note that the RA and Dec of each merged source are now defined to be exactly the position of the shortest wavelength detection in each case with the epoch attribute now being propagated from the detection table. For a query showing how to extract passband attributes from gpsDetection that are not present in gpsSource, see the example in the Q&A page.
  • The suite of cross-matched external surveys now includes the x-ray source catalogue from 2XMM.

The charts linked below show the status of the UKIDSS surveys in this release. This third release, like the DR2plus release, only contains one database, DR3plus, which contains all the data, i.e. includes data from fields that have incomplete waveband coverage as prescribed by a given survey. The WSA DR3plus release contains views of the survey source tables that allow users to easily target their queries at only those areas that have complete waveband coverage. The names of the source table views are lasYJHKsource, gpsJHKsource, gcsZYJHKsource and dxsJKsource. These names reflect the required waveband coverage. They appear in the schema browser under both the table and view sections. The UDS being only one field that now has coverage in J, H and K does not require a view.

DR3 Release Summary

Survey No. of multiframes No. of objects in
detection table
No. of sources in
source table
Approximate depths Plots
LAS 252,388 73,798,957 36,250,945 Y=20.2, J=19.6, H=18.8, K=18.2 link
GPS 175598 837,876,411 493,446,656 J=19.8, H=19.0, K=18.1 link
GCS 84,359 63,605,162 32,791,104 Z=20.4, Y=20.1, J=19.6, H=18.8, K=18.2 link
DXS 173,332 10,395,857 1,245,816 J=20.9-22.4,K=19.2-21.2 link
UDS 47953 2,587,440 96,558 J=22.9, H=21.5, K=21.8 link


See generic issues and bugs noted under Known Issues


  • January 31st 2008: GPS data added
    The DR3 release now contains GPS data.

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