The first hour of every LBA experiment is used for setup and fringe testing. In the past this has been added for PIs, but we are now asking PIs to add this setup themselves. Please note that this is really important to check setup problems and failing to do this properly could result in losing all data for one or more telescopes. Do not be tempted to cut the fringe test short. It's fine to allow slew time from the fringe test source to be onsource at the end of the setup period.
You should choose a single source to observe for the entire time. You need to choose the brightest, most compact source that is visible to all telescopes at your given LST. There are trade off needs due when including the longest baselines (Hart) or at higher frequencies (22 GHz). The choice of best source depends on the observing frequency.
Preferably choose one of the following sources and consult with CASS staff if you cannot find a suitable sorurce for your timeslot.
|Source||LST rise||LST set||Notes|
|3c279||9:09:37||16:42:45||Good at 20 GHz|
The typical stanza to include fringe test would be something like:
year = 2015 day = 273 start = 19:00:00 station = ATCA, MOPRA, PARKES, HOB_DBBC, CDDBBC, HART, WARK12M, ASKAP, KATHERIN, YARRAGAD group=1 repeat=14 grabto='file' grabtime=2,10 SOURCE=0208-512 GAP=1:00 DUR=3:00 intent='FIND_FRINGE' / intent='OBSERVE_TARGET' grabto='none'
Note that the
grabto is needed for Mark5 recorders. This grabs 2 seconds of data starting 10 seconds before the end of the scan. If you know there are no mark5 recorders being used, you can omit this and set gap to 0:00.