Antenna shadowing changes the illumination pattern of the shadowed antenna, and may produce some interference. Data is not aquired for projected antenna spacings smaller than 17 nanosecs (5.1m). Because of the heavy taper in the antenna illumination pattern, the 1m overlap of the 6.1m diameter antennas does not produce significant distortions of the amplitude and phase, and allows a slightly larger hour angle range to be observed. Data shadowed by a larger diameter may be omitted in the data reduction if desired.
Observers should check for antenna shadowing when preparing observing files for the compact antenna configuration. If the observations of the calibrator are shadowed, then it may not be possible to calibrate the data. If the passband observation is shadowed, then it may not be possible to calibrate the passband.
Here is a script to generate a list of shadowed data. The vms version is very similar. Remember that if an antenna is shadowed then all baselines using that antenna are shadowed even if the projected spacing, sqrt(u**2 + v**2), is greater than the antenna diameter. A list of shadowed uvdata for the c array for selected declinations follows.
#!/bin/csh -vf
# shadow.csh
# List shadowed uvdata for selected antenna array and declinations
# mchw 11 June 1991
rm -r dec*
echo "First run uvtrack interactively to define the antenna configuration."
echo "Then run uvtrack for various declinations."
uvtrack mode=batch source=dec-20 dec=-20 harange=-6,6,.5 out=dec-20 ant=c1.ant
uvlist vis=dec-20 line=wide recnum=100 'select=shadow(6)' log=log-20
cat log-20
uvtrack mode=batch source=dec0 dec=0 harange=-6,6,.5 out=dec0 ant=c1.ant
uvlist vis=dec0 line=wide recnum=100 'select=shadow(6)' log=log0
cat log0
uvtrack mode=batch source=dec20 dec=20 harange=-6,6,.5 out=dec20 ant=c1.ant
uvlist vis=dec20 line=wide recnum=100 'select=shadow(6)' log=log20
cat log20
uvtrack mode=batch source=dec40 dec=40 harange=-6,6,.5 out=dec40 ant=c1.ant
uvlist vis=dec40 line=wide recnum=100 'select=shadow(6)' log=log40
cat log40
cat log-20 log0 log20 log40 > shadow.list
end:
------------------------------------------------------------
Note: The UT times are one sample interval greater than the lst
All the shadowed uvdata from HA -6 to +6 is listed.
(The elevation is less than 0 for low declination.)
HA = Time - 6.5 hours.
------------------------------------------------------------
c1 configuration
40W 80E 0N
Antenna 1 is shadowed by antenna 3 when the source is in the east. Antenna 3 is
shadowed by antenna 1 when the source is in the west.
***** UV Listing for dec-20 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 4.10 1.000 0
2 00:30:00.0 1- 3 0.00 1.37 1.000 0
4 01:00:00.0 1- 2 1.57 4.07 1.000 0
5 01:00:00.0 1- 3 0.52 1.36 1.000 0
7 01:30:00.0 1- 2 3.11 3.96 1.000 0
8 01:30:00.0 1- 3 1.04 1.32 1.000 0
10 02:00:00.0 1- 2 4.59 3.79 1.000 0
11 02:00:00.0 1- 3 1.53 1.26 1.000 0
65 11:00:00.0 1- 3 1.53 -1.26 1.000 0
66 11:00:00.0 2- 3 -3.06 2.53 1.000 0
68 11:30:00.0 1- 3 1.04 -1.32 1.000 0
69 11:30:00.0 2- 3 -2.07 2.64 1.000 0
71 12:00:00.0 1- 3 0.52 -1.36 1.000 0
72 12:00:00.0 2- 3 -1.04 2.71 1.000 0
74 12:30:00.0 1- 3 0.00 -1.37 1.000 0
75 12:30:00.0 2- 3 0.00 2.74 1.000 0
***** UV Listing for dec0 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 0.00 1.000 0
2 00:30:00.0 1- 3 0.00 0.00 1.000 0
3 00:30:00.0 2- 3 0.00 0.00 1.000 0
4 01:00:00.0 1- 2 1.57 0.00 1.000 0
5 01:00:00.0 1- 3 0.52 0.00 1.000 0
6 01:00:00.0 2- 3 -1.04 0.00 1.000 0
7 01:30:00.0 1- 2 3.11 0.00 1.000 0
8 01:30:00.0 1- 3 1.04 0.00 1.000 0
10 02:00:00.0 1- 2 4.59 0.00 1.000 0
11 02:00:00.0 1- 3 1.53 0.00 1.000 0
13 02:30:00.0 1- 2 6.00 0.00 1.000 0
14 02:30:00.0 1- 3 2.00 0.00 1.000 0
62 10:30:00.0 1- 3 2.00 0.00 1.000 0
63 10:30:00.0 2- 3 -4.00 0.00 1.000 0
65 11:00:00.0 1- 3 1.53 0.00 1.000 0
66 11:00:00.0 2- 3 -3.06 0.00 1.000 0
68 11:30:00.0 1- 3 1.04 0.00 1.000 0
69 11:30:00.0 2- 3 -2.07 0.00 1.000 0
70 12:00:00.0 1- 2 1.57 0.00 1.000 0
71 12:00:00.0 1- 3 0.52 0.00 1.000 0
72 12:00:00.0 2- 3 -1.04 0.00 1.000 0
73 12:30:00.0 1- 2 0.00 0.00 1.000 0
74 12:30:00.0 1- 3 0.00 0.00 1.000 0
75 12:30:00.0 2- 3 0.00 0.00 1.000 0
***** UV Listing for dec20 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 -4.10 1.000 0
2 00:30:00.0 1- 3 0.00 -1.37 1.000 0
4 01:00:00.0 1- 2 1.57 -4.07 1.000 0
5 01:00:00.0 1- 3 0.52 -1.36 1.000 0
7 01:30:00.0 1- 2 3.11 -3.96 1.000 0
8 01:30:00.0 1- 3 1.04 -1.32 1.000 0
10 02:00:00.0 1- 2 4.59 -3.79 1.000 0
11 02:00:00.0 1- 3 1.53 -1.26 1.000 0
65 11:00:00.0 1- 3 1.53 1.26 1.000 0
66 11:00:00.0 2- 3 -3.06 -2.53 1.000 0
68 11:30:00.0 1- 3 1.04 1.32 1.000 0
69 11:30:00.0 2- 3 -2.07 -2.64 1.000 0
71 12:00:00.0 1- 3 0.52 1.36 1.000 0
72 12:00:00.0 2- 3 -1.04 -2.71 1.000 0
74 12:30:00.0 1- 3 0.00 1.37 1.000 0
75 12:30:00.0 2- 3 0.00 -2.74 1.000 0
***** UV Listing for dec40 ****
Options: brief,data
No. channels: 0, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
No shadowed data for dec40.
c2 configuration
40W 40N 100N
Antenna 2 is shadowed by antenna 1 when the source is in the west.
***** UV Listing for dec-20 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
55 09:30:00.0 1- 2 1.01 1.29 1.000 0
57 09:30:00.0 2- 3 -2.73 3.39 1.000 0
58 10:00:00.0 1- 2 0.40 1.26 1.000 0
60 10:00:00.0 2- 3 -3.06 3.52 1.000 0
61 10:30:00.0 1- 2 -0.23 1.25 1.000 0
63 10:30:00.0 2- 3 -3.34 3.66 1.000 0
64 11:00:00.0 1- 2 -0.84 1.28 1.000 0
66 11:00:00.0 2- 3 -3.56 3.81 1.000 0
67 11:30:00.0 1- 2 -1.45 1.33 1.000 0
69 11:30:00.0 2- 3 -3.73 3.98 1.000 0
No shadowed data for dec0.
No shadowed data for dec20.
No shadowed data for dec40.
c0 configuration
15E 15W 20N
For low declinations Antenna 3 is shadowed by 1 when the source is in the east
and shadowed by antenna 2 when the source is in the west. For highdeclinations
Antenna 2 is shadowed by 1 when the source is in the east and antenna 1 is
shadowed by antenna 2 when the source is in the west.
***** UV Listing for dec-20 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 -1.03 1.000 0
2 00:30:00.0 1- 3 1.29 0.93 1.000 0
3 00:30:00.0 2- 3 1.29 1.95 1.000 0
4 01:00:00.0 1- 2 -0.39 -1.02 1.000 0
5 01:00:00.0 1- 3 1.08 0.87 1.000 0
6 01:00:00.0 2- 3 1.47 1.89 1.000 0
7 01:30:00.0 1- 2 -0.78 -0.99 1.000 0
8 01:30:00.0 1- 3 0.85 0.83 1.000 0
9 01:30:00.0 2- 3 1.63 1.82 1.000 0
10 02:00:00.0 1- 2 -1.15 -0.95 1.000 0
11 02:00:00.0 1- 3 0.61 0.80 1.000 0
12 02:00:00.0 2- 3 1.76 1.75 1.000 0
13 02:30:00.0 1- 2 -1.50 -0.89 1.000 0
14 02:30:00.0 1- 3 0.36 0.78 1.000 0
15 02:30:00.0 2- 3 1.86 1.66 1.000 0
16 03:00:00.0 1- 2 -1.83 -0.81 1.000 0
17 03:00:00.0 1- 3 0.11 0.77 1.000 0
18 03:00:00.0 2- 3 1.93 1.58 1.000 0
20 03:30:00.0 1- 3 -0.15 0.77 1.000 0
21 03:30:00.0 2- 3 1.97 1.49 1.000 0
23 04:00:00.0 1- 3 -0.41 0.78 1.000 0
24 04:00:00.0 2- 3 1.97 1.40 1.000 0
26 04:30:00.0 1- 3 -0.66 0.80 1.000 0
27 04:30:00.0 2- 3 1.94 1.32 1.000 0
29 05:00:00.0 1- 3 -0.89 0.84 1.000 0
30 05:00:00.0 2- 3 1.88 1.23 1.000 0
32 05:30:00.0 1- 3 -1.12 0.88 1.000 0
33 05:30:00.0 2- 3 1.78 1.15 1.000 0
35 06:00:00.0 1- 3 -1.32 0.94 1.000 0
36 06:00:00.0 2- 3 1.65 1.07 1.000 0
38 06:30:00.0 1- 3 -1.50 1.00 1.000 0
39 06:30:00.0 2- 3 1.50 1.00 1.000 0
41 07:00:00.0 1- 3 -1.65 1.07 1.000 0
42 07:00:00.0 2- 3 1.32 0.94 1.000 0
44 07:30:00.0 1- 3 -1.78 1.15 1.000 0
45 07:30:00.0 2- 3 1.12 0.88 1.000 0
47 08:00:00.0 1- 3 -1.88 1.23 1.000 0
48 08:00:00.0 2- 3 0.89 0.84 1.000 0
50 08:30:00.0 1- 3 -1.94 1.32 1.000 0
51 08:30:00.0 2- 3 0.66 0.80 1.000 0
53 09:00:00.0 1- 3 -1.97 1.40 1.000 0
54 09:00:00.0 2- 3 0.41 0.78 1.000 0
56 09:30:00.0 1- 3 -1.97 1.49 1.000 0
57 09:30:00.0 2- 3 0.15 0.77 1.000 0
58 10:00:00.0 1- 2 -1.83 0.81 1.000 0
59 10:00:00.0 1- 3 -1.93 1.58 1.000 0
60 10:00:00.0 2- 3 -0.11 0.77 1.000 0
61 10:30:00.0 1- 2 -1.50 0.89 1.000 0
62 10:30:00.0 1- 3 -1.86 1.66 1.000 0
63 10:30:00.0 2- 3 -0.36 0.78 1.000 0
64 11:00:00.0 1- 2 -1.15 0.95 1.000 0
65 11:00:00.0 1- 3 -1.76 1.75 1.000 0
66 11:00:00.0 2- 3 -0.61 0.80 1.000 0
67 11:30:00.0 1- 2 -0.78 0.99 1.000 0
68 11:30:00.0 1- 3 -1.63 1.82 1.000 0
69 11:30:00.0 2- 3 -0.85 0.83 1.000 0
70 12:00:00.0 1- 2 -0.39 1.02 1.000 0
71 12:00:00.0 1- 3 -1.47 1.89 1.000 0
72 12:00:00.0 2- 3 -1.08 0.87 1.000 0
73 12:30:00.0 1- 2 0.00 1.03 1.000 0
74 12:30:00.0 1- 3 -1.29 1.95 1.000 0
75 12:30:00.0 2- 3 -1.29 0.93 1.000 0
***** UV Listing for dec0 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 0.00 1.000 0
2 00:30:00.0 1- 3 1.29 1.53 1.000 0
3 00:30:00.0 2- 3 1.29 1.53 1.000 0
4 01:00:00.0 1- 2 -0.39 0.00 1.000 0
5 01:00:00.0 1- 3 1.08 1.53 1.000 0
6 01:00:00.0 2- 3 1.47 1.53 1.000 0
7 01:30:00.0 1- 2 -0.78 0.00 1.000 0
8 01:30:00.0 1- 3 0.85 1.53 1.000 0
9 01:30:00.0 2- 3 1.63 1.53 1.000 0
10 02:00:00.0 1- 2 -1.15 0.00 1.000 0
11 02:00:00.0 1- 3 0.61 1.53 1.000 0
12 02:00:00.0 2- 3 1.76 1.53 1.000 0
13 02:30:00.0 1- 2 -1.50 0.00 1.000 0
14 02:30:00.0 1- 3 0.36 1.53 1.000 0
15 02:30:00.0 2- 3 1.86 1.53 1.000 0
16 03:00:00.0 1- 2 -1.83 0.00 1.000 0
17 03:00:00.0 1- 3 0.11 1.53 1.000 0
18 03:00:00.0 2- 3 1.93 1.53 1.000 0
20 03:30:00.0 1- 3 -0.15 1.53 1.000 0
21 03:30:00.0 2- 3 1.97 1.53 1.000 0
23 04:00:00.0 1- 3 -0.41 1.53 1.000 0
24 04:00:00.0 2- 3 1.97 1.53 1.000 0
26 04:30:00.0 1- 3 -0.66 1.53 1.000 0
27 04:30:00.0 2- 3 1.94 1.53 1.000 0
29 05:00:00.0 1- 3 -0.89 1.53 1.000 0
30 05:00:00.0 2- 3 1.88 1.53 1.000 0
32 05:30:00.0 1- 3 -1.12 1.53 1.000 0
33 05:30:00.0 2- 3 1.78 1.53 1.000 0
44 07:30:00.0 1- 3 -1.78 1.53 1.000 0
45 07:30:00.0 2- 3 1.12 1.53 1.000 0
47 08:00:00.0 1- 3 -1.88 1.53 1.000 0
48 08:00:00.0 2- 3 0.89 1.53 1.000 0
50 08:30:00.0 1- 3 -1.94 1.53 1.000 0
51 08:30:00.0 2- 3 0.66 1.53 1.000 0
53 09:00:00.0 1- 3 -1.97 1.53 1.000 0
54 09:00:00.0 2- 3 0.41 1.53 1.000 0
56 09:30:00.0 1- 3 -1.97 1.53 1.000 0
57 09:30:00.0 2- 3 0.15 1.53 1.000 0
58 10:00:00.0 1- 2 -1.83 0.00 1.000 0
59 10:00:00.0 1- 3 -1.93 1.53 1.000 0
60 10:00:00.0 2- 3 -0.11 1.53 1.000 0
61 10:30:00.0 1- 2 -1.50 0.00 1.000 0
62 10:30:00.0 1- 3 -1.86 1.53 1.000 0
63 10:30:00.0 2- 3 -0.36 1.53 1.000 0
64 11:00:00.0 1- 2 -1.15 0.00 1.000 0
65 11:00:00.0 1- 3 -1.76 1.53 1.000 0
66 11:00:00.0 2- 3 -0.61 1.53 1.000 0
67 11:30:00.0 1- 2 -0.78 0.00 1.000 0
68 11:30:00.0 1- 3 -1.63 1.53 1.000 0
69 11:30:00.0 2- 3 -0.85 1.53 1.000 0
70 12:00:00.0 1- 2 -0.39 0.00 1.000 0
71 12:00:00.0 1- 3 -1.47 1.53 1.000 0
72 12:00:00.0 2- 3 -1.08 1.53 1.000 0
73 12:30:00.0 1- 2 0.00 0.00 1.000 0
74 12:30:00.0 1- 3 -1.29 1.53 1.000 0
75 12:30:00.0 2- 3 -1.29 1.53 1.000 0
***** UV Listing for dec20 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 1.03 1.000 0
3 00:30:00.0 2- 3 1.29 0.93 1.000 0
4 01:00:00.0 1- 2 -0.39 1.02 1.000 0
6 01:00:00.0 2- 3 1.47 0.99 1.000 0
7 01:30:00.0 1- 2 -0.78 0.99 1.000 0
9 01:30:00.0 2- 3 1.63 1.06 1.000 0
10 02:00:00.0 1- 2 -1.15 0.95 1.000 0
12 02:00:00.0 2- 3 1.76 1.13 1.000 0
13 02:30:00.0 1- 2 -1.50 0.89 1.000 0
15 02:30:00.0 2- 3 1.86 1.22 1.000 0
16 03:00:00.0 1- 2 -1.83 0.81 1.000 0
18 03:00:00.0 2- 3 1.93 1.30 1.000 0
58 10:00:00.0 1- 2 -1.83 -0.81 1.000 0
59 10:00:00.0 1- 3 -1.93 1.30 1.000 0
61 10:30:00.0 1- 2 -1.50 -0.89 1.000 0
62 10:30:00.0 1- 3 -1.86 1.22 1.000 0
64 11:00:00.0 1- 2 -1.15 -0.95 1.000 0
65 11:00:00.0 1- 3 -1.76 1.13 1.000 0
67 11:30:00.0 1- 2 -0.78 -0.99 1.000 0
68 11:30:00.0 1- 3 -1.63 1.06 1.000 0
70 12:00:00.0 1- 2 -0.39 -1.02 1.000 0
71 12:00:00.0 1- 3 -1.47 0.99 1.000 0
73 12:30:00.0 1- 2 0.00 -1.03 1.000 0
74 12:30:00.0 1- 3 -1.29 0.93 1.000 0
***** UV Listing for dec40 ****
Options: brief,data
No. channels: 1, Linetype: wide
Line Start: 1.000, Width: 1.000, Step: 1.000
------------------------------------------------------------
Vis # Time Ant U(kLam) V(kLam) Amp Phase
1 00:30:00.0 1- 2 0.00 1.93 1.000 0
3 00:30:00.0 2- 3 1.29 0.21 1.000 0
4 01:00:00.0 1- 2 -0.39 1.91 1.000 0
6 01:00:00.0 2- 3 1.47 0.33 1.000 0
7 01:30:00.0 1- 2 -0.78 1.86 1.000 0
9 01:30:00.0 2- 3 1.63 0.46 1.000 0
10 02:00:00.0 1- 2 -1.15 1.78 1.000 0
12 02:00:00.0 2- 3 1.76 0.60 1.000 0
64 11:00:00.0 1- 2 -1.15 -1.78 1.000 0
65 11:00:00.0 1- 3 -1.76 0.60 1.000 0
67 11:30:00.0 1- 2 -0.78 -1.86 1.000 0
68 11:30:00.0 1- 3 -1.63 0.46 1.000 0
70 12:00:00.0 1- 2 -0.39 -1.91 1.000 0
71 12:00:00.0 1- 3 -1.47 0.33 1.000 0
73 12:30:00.0 1- 2 0.00 -1.93 1.000 0
74 12:30:00.0 1- 3 -1.29 0.21 1.000 0