Measured horn positions

08may04

nov12 horn surveys

    The horns are surveyed into position using a theodolite. A cap with targets is placed over the mouth of the horn. This cap has 5 targets  mounted at known positions. The theodolite shoots the secondary to define the  reference dome centerline coordinate system. The turret is moved to the correct position for this feed and then the targets on the horn cap are shot. This gives the cap location in dome centerline coordinates. The horn position is then computed using the distance from the horn cap to the horn phase center.  The positions are then converted to focus coordinate system where z is along the paraxial ray, y is toward the stairwell, and x is up the elevation rails. The table below shows the corrections that must be made to the horns to put them at the nominal positions (you move in the direction of the correction).
NOTES:
  • When moving the turret, increasing the turret encoder angle moves a horn at focus towards the stairwell (+y).
  • The Alfa receiver wants to be located -1.063 inches in x from the nominal position to balance the uphill and downhill horns. The values reported are relative to this position.

  • KEY:

  • Note: Lynn's memos show the error. The xxC are the corrections (or minus the errors).
  • xxC  Translation correction. Distance to move in focus coordinates to correct error. +X uphill,+Y toward stairwell, +Z up focus direction.
  • TxC Rotation correction(right handed). TYC + is clockwise around Y axis. TXC + is clockwise about +X axis.
  • <-- This marks the most recent survey for this receiver
  • X + along azimuth arm. Y perpendicular to az arm + is toward the stairwell. Z is along the focus direction + makes the  focal length longer.
  • nominal: this is the nominal position for the measurement in the focus (ray trace coordinates). If you subtract the correction from the nominal, you will get the current reading.

  •  
    HORN SURVEY RESULTS
    Feed
    turDeg
    XC
    Inches
    YC
    Inches
    ZC
    Inches
    TYC
    Deg
    TXC
    Deg
    notes
    nominal
     
     -354.00
     0.
     -234.0
    1.74 
     0.
     
    nominal
    31oct12

    -248.145
    0.
    -389.822
    .63
    0
    Not sure why these differ so much
    from the previous set?
    These are positions, not corrections.l
             LBN      
    28jan00
    309.12
    -.193
    .104
    .296
     .099
    -.7779
    <--see #4.
      21aug02
     
     
     
     
     
     
       see #9
     
         
     LBW
         
    28jan00
    285.5
    -.124
    -.922
    -.048
     -.225
    .9985
    see #5. 
    11feb04
    286.52
    -.46
    -1.36
    1.00
    .22
    .97
     
    14feb04
    285.42
    -.47
    -.03
    1.00
    .23
    -.76
     see  #12
    28apr04
    285.42
    -.93
    -.07
    .94
       
    02nov12
    285.477
    -.794
    .126
    .896
    .390
    .738
    <-- see survey notes
           
    ALFA
         
    28apr04
    26.27
    -.42*
    0
    -.51
       
     see #15
    02may02 26.64           see survey notes.
    02nov12
    26.403
    .741
    .07
    -.517
    .353
    -.129
    <-- see survey notes
     
     
     
     
    SBN
     
     
     
    28jan00
    76.6
    -.003
    .292
    .112
      -.069
     -.1328
     
    28jan00
    76.6
    -.038
    .253
    .079
     -.057
    -.1620
    see #1
    04feb02
    76.83
    -.021
    -.257
    .158
     -.028
     -.0743
     
    29mar02
    76.88
    -.013
    -.132
    .123
     -.032
     -.1558
     #8
    11feb04
    76.83
    -.13
    -.35
    .02
    -.07
    -.05
     
    14feb04
    76.56
    -.07
    -.05
    -.11
    .04
    .20
    see # 12
    28apr04
    76.555
    -.59
    -.02
    -.26
     
     

    02may04
    76.90
    -0.59
    -0.01
    -0.20
       
    08may04
    76.94
     
      .01
     
     
     
    see survey notes
    31oct12

    79.6143
    -.236
    +.01
    +1.173
    -.45
    -.51
    <-- see survey notes
    turret later moved to 79.967
     
     
     
     
     SBTX
     
     
     
    28jan00
    62.25
    -.143
    .093
    -.067
     -.086
     .3677
    see #6 
    11feb04
    62.16
    -.25
    -.24
    -.19
    .00
    .31
     
    14feb04
    61.97
    -.20
    -.06
    -.27
    .01
    -.32
     see # 12
    28apr04
    61.96
    -.62
    -.01
    -.43
         
    02may04
    62.29
    -0.66
     -0.00
    -0.38
       
    <--
    08may04
    62.29
     
    -.02
     
     
     
    see survey notes
    31oct12
    61.9441
    -.518
    +.181
    +.122
    1.2
    .2
    <-- see survey notes
     
         
     SBW
         
    28jan00
    103.8
    .447
    .141
    -.379
     -.821
     .3547
    see #7
    11feb04
    103.88
    -.14
    -.28
    -2.54
    .25
    .5
     
    14feb04
    103.66
    -.09
    -.07
    -2.64
    .17
    -.55
     see # 12,#14
    28apr04
    103.66
    -.58
    .01
    -.269
     
       
    02may04
    104.03
    -0.24
    0.01
    -2.80
       
    02nov12
    103.673
    -.152
    .085
    -.021
    .536
    .479
    <-- see survey notes
     
     
     
     
     SBH
     
     
     
    29mar02
    124.99
    -0.027
    1.068
    .703
    .284 
     -.6941
     see #8
    11feb04
    125.83
    -.12
    -.36
    -.91
    .23
    -.56
     
    14feb04
    125.55
    -.08
    -.05
    -.12
    .31
    .59
     see  #12 ,#13
    28apr04
    125.55
    -.53
    0
    -.23
     
     
     
    02may04
     125.94
    -0.15
    0.02
    -0.08
       
    02nov12
    125.717
    -.132
    .076
    .084
    .279
    -.571
    <-- see survey notes
     
     
     
     
     CB
     
     
     
    28jan00
    206.65
    -.124
    -.001
    .010
     .410
     -.1998
     
    28jan00
    206.65
    -.165
    .023
    0.020
    .396 
     -.2013
    repeated 
    28aug02
               
    see #10
    11feb04
    206.65
    -.17
    -.34
    -.11
    .17
    -.42
     
    14feb04
    206.38
    -.15
    -.05
    -.17
    .32
    .43
    see # 12
    28apr04
    206.38
    -.66
    .05
    -.21
     
     
    02may04
    206.77
    0.01
    0.01
    -0.29
       
    02nov12
    206.556
    -.008
    .039
    -.214
    .524
    -.489
    <-- see survey notes
     
     
     
     
     CBH_1
     
     
     
    11feb04
    164.57
    -.13
    -.14
    2.33
    .27
    .96
     
    14feb04
    164.67
    .23
    0.00
    .36
    -.74
    -.34
     
    28apr04
    164.67
    -.28
    .01
    .23
         
    02may04
    165.01
    -0.22
    0.00
    0.05
        <--
    08may04
    165.03
     
    .02
     
       
    see survey notes
    02nov12
    164.711
    -.428
    .073
    .159
    .435
    .438
    <-- see survey notes
     
     
     
     
     CBH_2
     
     
     
    11feb04
    158.45
    .05
    -.71
    2.28
    .27
    -.42
     
    14feb04
    158.01
    .51
    -.03
    .34
    -.69
    .86
     
    02may04
    158.38
     
     
     
     
     
    <--see survey notes
     
     
     
     
    XB
     
     
     
    04feb02
    161.99
    -.085
    -.449
    .441
     .259
     .0412
    see #2.
    29mar02
    162.39
    -.066
    -1.131
    -.011
     .097
     -.1208
    see #3.
    08jan04
    309.94
             
     see #11
    11feb04
    309.94
    -.17
    -.28
    -.11
    .1
    -.82
     
    14feb04
    309.72
    -.15
    .02
    -.19
    .22
    .90
    see #12
    28apr04
    309.72
    -.43
    .07
    -.15
         
    02may04
    310.06
    -0.22
    -0.00
    -0.14
       
    02nov12
    309.800
    -.185
    .045
    -.121
    .385
    -.811
    <-- see survey notes
    1. The beam under the floor by the sbn receiver was removed to work on the seti IF box. This caused the floor to shift. The beam was replaced and then this receiver was remeasured. After the measurement, the turret position was moved to 76.83 deg.
    2. After the measurement the horn was moved up .44 inches. The turret was moved 161.99 -> 162.34. This turned out to be the wrong turret direction to move. The next survey measured twice the error.
    3. The large y error was because the turret was moved the wrong direction on 04feb02. After the measurement the turret was moved to 161.50.
    4. After the measurement, the lbn turret position was moved to 310.14.
    5. After the measurement the lbw turret position was changed to 286.52. This looks like it was the WRONG direction.
    6. After the measurement, the sbtx turret position was moved to 62.16 deg. This was the WRONG direction
    7. After the measurement the sbw turret position was moved to 103.8->103.88 degrees.
    8. After the measurement (and getting the sign right!), the turret was moved, 124.99->125.827 degrees.
    9. 21aug02 lbn horn moved down 3.84 inches to correct for phase center error.
    10. 28aug02 cband horn moved down 1.08 inches to put phase center at focus.
    11. jan04    receivers moved on floor to get ready for alfa installation.
    12. 14feb04. The 11feb04 survey yCorrection was set to zero by moving the turret positions and then the 14feb04 survey was done.
    13. 14feb04 sbhigh was moved down .91 inches before the survey to put the phase center at focus.
    14. 14feb04 sbw was out of focus in z. It was not moved down because there was no more adjustment room on the mount. We need to make a new bracket.
    15. Alfa x listed is measuredCorrection - 1.063 . Alfa wants to be 1.063 downhill from the nominal focus to balance the outer feeds.

    Survey notes:



    31oct,02nov12 horn surveys (top)

        A new sband narrow horn was installed on 28oct12. Lynn surveyed the sbn and sbtx horns on 31oct12. He surveyed the rest of the horns on 02nov12. An "old" (pre may04) secondary reference file  was used for the theodolite shooting. This data set was used for the sbn and sbtx analysis. Lynn did a comparison with the old and "newer" secondary references and saw little difference. All of the other receivers were analyzed using the newer secondary reference derived from the 28jun04 videogrammetry.
        On 02may04 this "old" secondary reference was also used. At that time it was thought that there was a .45" y error between the two system (see 02may04 above).

    Some comments on the various receivers:

    Table showing the corrections needed from the nov12 surveys.

    rcvr
    turPos for
    measurement
    deg
    Xcor
    inches
    Ycor
    inches
    Zcor
    inches
    TYcor
    deg
    TZcor
    deg
    lbw
    285.477
    -.794
    .126
    .896
    .390
    .738
    alfa
    26.403
    .741
    .07
    -.517
    .353
    -.129
    sbn
    79.6143
    -.236
    +.01
    +1.173
    -.45
    -.51
    sbtx
    61.9441
    -.518
    +.181
    +.122
    1.2
    .2
    sbw
    103.673
    -.152
    .085
    -.021
    .536
    .479
    sbh
    125.717
    -.132
    .076
    .084
    .279
    -.571
    cb
    206.556
    -.008
    .039
    -.214
    .524
    -.489
    cbh
    164.711
    -.428
    .073
    .159
    .435
    .438
    xb
    309.800
    -.185
    .045
    -.121
    .385
    -.811


    Plotting the corrections for each receiver:

    The plot shows the x,y,z errors (in dome centerline coordinates) from the survey (.ps) (.pdf):

    Lynn's emails and reports:

    processing: /share/megs/survey/121102/hornsurvey.pro, /share/megs/survey/121031/xxx





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