A priori decisions for a tile (with known boundaries in RA/dec):
Determine the phase calibrator(s) for the tile. (I am currently doing this with an SCT cone search of the NRAO calibrator manual, looking for sources with P-code in both L and C band, and as close as possible to the tile center (within 15 degrees of the tile center if possible). –AEK)
Determine the flux calibrator for the tile based on location/proximity. Choose best, but in this order of preference:
1331+305=3C286 (suitable polarization angle calibrator)
0137+331=3C48 (suitable polarization angle calibrator)
0542+498=3C147 (NOT for polarization angle calibration; can be used for leakage WITH monitoring)
Guess at LST start range for the tile (I am currently doing this by examining the elevation pattern for the flux calibrator and the phase calibrator(s); this can also assist in making choice of flux calibrator. –AEK)
Determine whether phase calibrator is closer to the east or to the west edge of the tile. This will be the side to start from (parameter –rastart in OTF_scans_from_tile).
Use OTF_scans_from_tile.py to create a source list and scan list from the tile boundaries (see below).
Manually add a header to the scans.txt file containing info for Lorant’s code: # <flux cal> [beg/end] <LST start range> <phase cals>. The choice of “beg” or “end” is to indicate whether the flux calibrator will be observed first or last in the SB. For the moment, we plan to consistently observe the flux calibrator first. (An example header: # 3C286 beg 16:00-19:00 J2007+4029)
Use the scans file as input into Lorant’s code to create a file that can be uploaded to the OPT.
Upload the sources.txt file to the SCT and change the “Unnamed_Catalog” in the SCT to the name of the tile.
Upload the .4opt file to the OPT.
Manually modify the SB in the OPT to finalize. This includes:
ensure that the wrap is correct based on relative location of flux cal and tile (use wrap diagram)
add slew time to first phase calibrator scan (if necessary)
ensure that the scans have appropriate elevation (use block checker)
change (bulk edit) the Ready scans to DUR with the appropriate duration (e.g., 27 or 36 seconds) such that they have a very short but non-zero on-source time, i.e. between 0 and 9 seconds (use block checker)
double-check that the polarization leakage calibrator has large enough range of parallactic angle— >30d for “bright” calibrators (>1Jy), >60d for fainter calibrators (<1Jy, >0.5Jy)
Submit!
(Can determine overhead by comparing total SB length to the “Total OTF time” reported in the scans.txt file)