The pointing model
The pointing
model consists of 13 parameters in azimuth and za along with a za encoder
table. It is made using the sbn (2380Mhz) receiver.
The heiles calibration scans are used to measure the
source offsets at each az and za.
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2 crosses rotated by 45 degrees are done while tracking
a source. Each leg of a cross is +/- 3 beams and takes 60 seconds
to complete. 1 pattern takes about 5 to 6 minutes to complete.
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For each leg fit for the main beam and the 2 sidelobes.
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Remove the sidelobes and then do a 2d fit to the main
beam of the 4 legs.
The model made after alfa was installed and the kevlar
cables were installed on the feed tower in the dome:
A record of all
the models we've made at ao.
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