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jun12-dec12 sysperf,pnterror

jun12-dec12: sysperf, pnt error

jan 2013

Calibration data from jun12 through dec12 was used to look at the system performance and pointing errors of various receivers.

History:

06jun12 - model 18 installed.

All calibration data was taken after this date.

19oct12 - jennings relay from 430 dome polB removed. Prior to this, little power was getting into polB.

430 dome data used was after 19oct12.

28oct12: new sbn receiver installed
26nov12: sbn receiver moved up in z direction 1.2 inches

sbn data used was taken after 26nov12.

Processing:

For each receiver, calibration data for the specified range was extracted from the datasets.
calibration scans were excluded if:

they had an exceptionally large pointing error for this receiver (say > 60 asecs)
the computed gain was very low (< 1 K/Jy)
These were to throw out scans with problems.

There was no data for:

800Mhz rcvr
sbh
alfa

The plots:

For each receiver 3 sets of plots were made:

Page 1: calibration results:

gain, Tsys,Sefd, and average beam widths.

All plotted vs za.

Colors show different frequencies
symbols show different sources.
The sources are listed to the left of the plots

Page 2: pointing errors:

Top 2 frames: za error vs za and az
Bottom 2 frames: az error vs za and az.
The mean and rms for the za and az errors are printed in the upper left.

Page 3: arrow plot showing the pointing errors across the dish.

The length shows the pointing error. 1 tick mark is 10 asecs
the angle of the arrow shows the pointing error direction.
Plot directions:

top: feed in north.. looking at southern sources
bottom: feed in the south.. looking at northern sources
left: feed in west. Looking at rising sources.
each circle if 5 degrees in za.

Table of plots:

Rcv calibration and pointing error plots	avg pointing errors Asecs				Updated model offsets 13jan13
	za errors		azimuth errors
	mean	rms	mean	rms
327 (.ps) (.pdf)	9.9	12.5	4.1	10.6	yes
430Dome (.ps) (.pdf)	22.3	8.6	25.4	8.7	yes
lbw (.ps) (.pdf)	4.1	4.0	.07	6.7	yes
sbn (.ps) (.pdf)	-11.3	3.9	-9.7	4.9	yes
sbw (.ps) (.pdf)	9.0	3.1	6.2	5.6	yes
cb (.ps) (.pdf)	3.8	4.0	2.8	5.2	yes
cbh (.ps) (.pdf)	2.5	4.5	1.3	4.5	no
xb (.ps) (.pdf)	.8	4.1	-.1	7.1	no

Updating pointing offsets:

The model includes an offset in az,za that should make the mean error 0.

The offset is normally computed from the model. This uses sbn and 20 sources covering the entire dish. The offsets for the other receivers are then computed relative to sbn using 2 or 4 sources.This was done back in apr-may12.
With the installation of the new sbn receiver, the standard model offset (from the 20 sources) is no longer valid for the sbn receiver. So it's offsets had to be updated from the sources after the installation.
I decided to update the other receiver offsets so everything changes at the same epoch (even though there is not complete dish coverage).

Some receiver notes:

430: there is a large beam squint between polA and polB
sbn. the pointing offsets are from the installation of the new feed
cbh,xb: pointing offsets not large enough to bother updating.

processing: ~x101/130112/pnter.pro

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