• If you are citizen of an European Union member nation, you may not use this service unless you are at least 16 years old.

  • You already know Dokkio is an AI-powered assistant to organize & manage your digital files & messages. Very soon, Dokkio will support Outlook as well as One Drive. Check it out today!



Page history last edited by Ray Norris 3 years, 9 months ago

Overall aim: 

The establishment of 3 reference fields (at dec -30, 0, 30) to be observed by all major radio telescopes (JVLA, Westerbork, ATCA, ASKAP, Meerkat, e-MERLIN, GMRT, DRAO, LOFAR, etc) and SKA pathfinder surveys to check on calibration accuracy and systematics between surveys. Originally suggested by Jim Condon, Leiden, Feb 2011 


The Fields

Dec +30: SLOAN field at 15h 30m, +29° 00’ (J2000)


Dec -30: CDFS-SWIRE 




Flux densities

Corrections at low SNR

Source counts





Current Status

Dec +30: SLOAN field

  • Field centre 15h 30m, +29° 00’ (J2000)
  • Observed by
  • WSRT (1.4 GHz) - Oosterloo & Rottgering
  • e-MERLIN (1.5GHz) 7-point masaic of a sub-region covering 1 degree diameter. High-resolution survey (Morphological identification of sources) Programmes CY6215 & CY7221 - Wrigley, Muxlow, Beswick, Molden, Radcliffe, & Thomson
  • DRAO (408 MHz + 1.4 GHz (incl. polarization) + HI) - Kothes, Kronberg, Landecker, Norris & Rupen
  • ATCA (1.4 GHz) - Norris  et al.
  • VLA - observed with VLASS - quicklook images should be available in May 2018 


  • Field centre 10:00:24  02:10:55 (J2000)
  • Observed by JVLA at 1.4-2.1 GHz as aprt of COSMOS program
  • VLA - observed with VLASS - quicklook images should be available in May 2018 



  • Field centre: 03:31:30, -28:00:00 (J2000)
  • ATCA @1.4, 2.3GHz(ATLAS field) - Norris et al
  •  MOST@843MHz - Hunstead, Norris, Chow, et al
  •  MWA@200 MHz - Seymour et al
  •  GMRT @ 150, 325 - Sirothia et al.
  •  Smaller areas with ATCA (5-35 GHz), VLA (1.4-2.1 GHz), GMRT (610 MHz)
  • VLA - observed with VLASS - quicklook images should be available in May 2018
  • ASKAP has observed the southern field (CDFS) from about 800-1400.  Higher frequency ASKAP observations (1400-1800) and ASKAP observations of the other fields are on our early science list for later in 2018, albeit at somewhat low priority (unless someone steps up to process and look at the data).



Update - 23-March-2020

     COVID-19 has disrupted projected observations of the Northern SLOAN Reference Field. Planned e-MERLIN observations as part of the 7-point mosaic have been postponed as  e-MERLIN operations have been temporarily halted.

          Initial work to establish reliable flux density calibrators for this field will continuie.

          TM to liase with reference field contact personnel at each observatory to establish a short list of flux density calibrators for each field to enable initial flux density scale comparisons to be established between observations of these fields made by the various instruments.



Comments (0)

You don't have permission to comment on this page.