Owen's Notes

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Revision as of 21:44, 17 March 2020 by Oweng (Talk | contribs)

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Update Antenna Pointing (17 March 2020)

Access the Pipeline Computer.

From the terminal, start ipython:

ipython --pylab

Import the calibration and Time libraries:

import calibration as cal

from util import Time

Load up the solar pointing scans for a given date and time.

x,y,qual=cal.solpntanal(Time(2020-03-17 18:30))

The above command will load the scans from the 17 March 2020 18:30 UT.

To view the beam widths as a function of frequency for each antenna and polarisation:

cal.sp_bsize(x,y)

To obtain the pointing offsets:

xoff,yoff,dx,dy=cal.sp_offsets(x,y)

This will display the offsets for each antenna and feed. Ideally the offsets should be at zero. If particular antennas significantly deviate from zero then a correction can be made.

For example, the following command will adjust the pointing offsets for antennas 6 to 8, 10 and 13:

cal.offsets2ants(Time('2020-03-17 18:30'),xoff,yoff,antst='ant6 ant7 ant8 ant10 ant13')

The newer antennas with the alt-az drives that have had tracking updated will need to be rebooted. From the Schedule Window issue the commands:

reboot 1 ant6-8

tracktable sun_tab.radec 1 ant6-8

track ant6-8

The antenna pointing adjustment is typically performed once per month.