UKIDSS LAS inter-waveband cadence

The UKIDSS LAS data is nominally taken with MSBs lasting 1hr in duration either Y and J or H and K in the same MSB. Within an MSB each of the two wavebands is observed continuously for half the time. Each MSB consists of a series of complete 4-pointing Tiles. Typically 4 to 5 tiles are observed in two bands per hourly MSB. The plots below show the difference is time between wavebands for DR1. DR1 and DR1+ are shown separately.

DR1 distributions

[could also do EDR and tabulate some centiles] Some features to note are:
  1. Y is observed before J with a median interval of around 25mins and 95% within 40mins. [see the differential Y-J plot with median -0.42hrs]
  2. Similarly H is observed before K with a median interval of around 25mins and 95% within 40mins. [see the differential Y-J plot with median -0.42hrs]
  3. The median interval between the YJ and HK observations is 2.20hrs(0.09days) with 45% of the OBs pairs separated by more than a day. i.e. 55% of YJ and HK OBs accur on the same night. 35% of the HK OBs are more than a day earlier that the YJ OBs and 15% are more than a day after the YJ OBs.
  4. The UT distribution of the OBs is similar in all wavebands.

    DR1 plots




    DR1plus plots


    Richard G. McMahon <rgm@ast.cam.ac.uk>
    Last modified: Thu Jan 18 16:54:07 2007