Observing log and notes for miniRF observations Feb 28, 2009

Links:
preliminary Processing/calibration miniRF summary page


Project code AGBT08B_049_04

Final timeline: from Ron S.

Some preliminary plots

Observing Logs

Summary of data Scans

    scan num start time (UT) what
    1-4 19:34 peak up on 0204+1514
    5-8 19:39 peak up on 0204+1514 : new LPCs +0.28, +0.61 arcmin
    9-10 19:45 ON/Off telemetry signal to check ephemeris
    11 19:48 60 sec track on telemetry
    12 19:54 set LOs, attens, track 60 sec on C1
    13-16 20:03 series of 5 min scans on C1 : adjust attenuations, settle on settings listed below
    17-22 20:39 cal scans on the Moon
    23-26 20:58 cal scans on Cygnus A
    27-30 21:28 cal scans on Cass A
    31-35 21:46 cal scans on 3C48
    36-37 22:07 track C1
    38-40 22:13 track telemetry
    41-42 22:20 configure for C1
    43 22:27 Track C1 : pass 2, 7-min scan - elev~52
    44-47 22:47 cal on 3C138
    48-51 23:06 cal on 3C147
    52-59 23:27 peak up on 0204+1514 : new LPCs -0.27, +0.27 arcmin
    60 23:40 check tracking on telemetry
    61-62 23:47 configure for C1
    63 00:02 Track C1 : pass 3, 7-min scan - elev~35

New standard Attenuator settings
    atten value (db)
    IFRack S1 14
    IFRack S3 8
    IFRack S5 10
    IFRack S7 7
    ConvRack CM1 12
    ConvRack CM5 14
    ConvRack CM11 25
    ConvRack CM15 30
    SP A1 23
    SP B1 38
    Rcvr2_3 +12 db


Commentary

    Weather was overcast, snow predicted. Outside temp ~37F.

    19:25 UT : Started ~5 minutes ahead of schedule (19:30 UT). Changed to S-band receiver and moved to a pointing calibrator (0204+1514, ~4 Jy) near the Moon. Baselines rather wobbly, either due to overcast weather with impending snow, or maybe RFI. Continuum observations for pointing were centered at 2232 MHz with a bandwidth of 80 MHz, so probably some RFI in the band. Tsys measured to be about 20 K. Fitted peaks were reasonable. Adopted local pointing corrections (LPCs) of +0.28, +0.61 arcmins.

    19:45 UT : moved to track the spacecraft to look for the telemetry signal at 2230.1 MHz. Balanced on C1 (that means attenuators were adjusted to optimum levels for the fiber tranceivers; i.e., not the levels determined for the miniRF signal). The telemetry signal was clearly seen on the spectrum analyzer and in the SP data.

    19:54 UT : tracked the spacecraft, set up for the miniRF signal at 2384.15 MHz.

    20:15 to 20:30 : collect data from miniRF. Try removing 4 and 8 db attenuation from the values determined yesterday. less attenuation apparently put the signal into saturation because the peak of the spectra did not increase. Settled on attenuator values given in the above table.

    20:39 to 22:00 : calibration scans on the Moon, Cass A, Cygnus A, 3C48. All were done both with standard attenuator settings as given in above table and with balancing on the source. The noise cals were switching at a 1 Hz rate.

    22:13 to 22:17 : track spacecraft, tune for telemetry. Telemetry signal seen both on spectrum analyzer and in SP data.

    22:21 : set up for pass 2

    22:27 to 22:34 : collect data from pass 2. Signal seen in SP spectra. Max amplitude about where we expect it at the middle of the pass.

    22:47 to 23:20 : calibration scans on 3C138 and 3C147. Noise cals switching.

    23:27 to 23:36 : check the pointing with more scans on 0204+1514. Baselines worse than before; Tsys about 35K

    23:40 to 23:43 : track C1, observe the telemetry. Signal seen clearly on spectrum analyzer and in SP spectra.

    23:47 to 23:57 : get ready for miniRF pass 3; set attenuators to standard settings. Noise cals off.

    00:02 to 00:09 : record pass 3. Data looked reasonable based on the on-line monitoring. Everything appeared to have gone well.


Antenna coordinates

Attached here are ascii dumps of antenna coordinates at 0.1 second intervals during main tracking scans.
Columns are: MJD, RA_J2000 (degrees), DEC_J2000(degrees), Azimuth(degrees), Elevation(degrees)


Some preliminary displays

From the Spectral Processor (SP). The vertical scale is "counts" : don't know as yet how this relates to real power. Whats plotted is the sum of the XX and YY products, i.e., the "I" stokes parameter.

  • Figs 1 and 2: a spectrum of one 1-second integration near the middle of pass 2: full spectrum, and zoom in on the signal.
  • Figs 3 and 4 : similarly for pass 3.

  • Fig 1: Scan 43 (pass 2) int# 173:
    scan43I int173.jpg

  • Fig 2: zoom in on Fig 1:
    scan43I int173zoom.jpg

  • Fig 3 : scan 63 (pass 3) int#171:
    scan63I int171.jpg

  • Fig 4: zoom in on Fig 3:
    scan63I int171zoom.jpg

Beam Patterns:

Figures 5 and 6 show the beam patterns in total power for passes 2 and 3. For these scans, the Spectral Processor was recording a spectrum every 0.5 seconds. The spectral processor records 4 spectra for each integration: the parallel and cross products designated XX, YY, XY, YX. The "I" polarization is XX+YY, and will probably not change significantly when the correct polarization calibration is applied. We added together the XX and YY spectra to get the total power, or "I", spectrum, then integrated over the portion of the spectrum having the signal, i.e. from about 2383 to 2385.3 MHz, as one can see from Figs 1-4. Thus one integrated total power value was determined for each 0.5 second sample and these values are plotted versus time from the beginning of the data taking. No idea yet what the correct amplitude calibration is, so these beam patterns are displayed in relative DB units. The spiky nature of the plots is presumably due to beating of the 0.5 sec sampling with the miniRF pulse pattern.
  • Fig 5 : total power for pass 2 (azimuth scan): relative DB scale.
    beampat I43.png

  • Fig 6: total power for pass 3 (elev scan): relative DB scale.
    beampat I63.png

Figures 7 and 8 show the beam patterns from the individual correlator channels of the Spectral Processor: XX, YY, XY, and YX. Of course there is yet no idea how these relate to Stokes parameters.
  • Fig 7 : Pass 2: patterns in XX,YY,XY,YX: on a linear scale.
    beampat xy43a.jpg

  • Fig 8 : Pass 3: patterns in XX,YY,XY,YX: on a linear scale.
    beampat xy63a.jpg


--
FrankGhigo - 28 Feb 2009

Topic attachments
I Attachment Action Size Date Who Comment
2009-02-23GBT_Cal_TimeLine_Final_PostTest.pdfpdf 2009-02-23GBT_Cal_TimeLine_Final_PostTest.pdf manage 121 K 2009-03-01 - 20:03 FrankGhigo Final Timeline from Ron
AGBT08B_049_04.summarysummary AGBT08B_049_04.summary manage 14 K 2009-03-01 - 10:35 FrankGhigo Scan Summary
AGBT08B_049_04_log.txttxt AGBT08B_049_04_log.txt manage 115 K 2009-03-01 - 10:37 FrankGhigo Scheduling scripts and logs
OpsLogsDetails.pdfpdf OpsLogsDetails.pdf manage 82 K 2009-03-01 - 20:01 FrankGhigo Telescope Operations Log
beampat_I43.pngpng beampat_I43.png manage 17 K 2009-03-03 - 14:41 FrankGhigo Fig 5 : total power for pass 2 (azimuth scan)
beampat_I63.pngpng beampat_I63.png manage 19 K 2009-03-03 - 14:42 FrankGhigo Fig 6: total power for pass 3 (elev scan)
beampat_xy43a.jpgjpg beampat_xy43a.jpg manage 303 K 2009-03-23 - 11:28 FrankGhigo Fig 7 : Pass 2: patterns in XX,YY,XY,YX
beampat_xy63a.jpgjpg beampat_xy63a.jpg manage 336 K 2009-03-23 - 11:29 FrankGhigo Fig 8 : Pass 3: patterns in XX,YY,XY,YX
s11_2009_02_28_194828_t2.txttxt s11_2009_02_28_194828_t2.txt manage 62 K 2009-03-02 - 10:01 FrankGhigo Antenna Tracking, scan #11
s15_2009_02_28_202048_t2.txttxt s15_2009_02_28_202048_t2.txt manage 310 K 2009-03-02 - 10:02 FrankGhigo Antenna Tracking, scan 15
s40_2009_02_28_221559_t2.txttxt s40_2009_02_28_221559_t2.txt manage 62 K 2009-03-02 - 10:02 FrankGhigo Antenna tracking, scan 40
s43_2009_02_28_222710_t2.txttxt s43_2009_02_28_222710_t2.txt manage 435 K 2009-03-02 - 10:03 FrankGhigo Antenna tracking, scan 43
s60_2009_02_28_233955_t2.txttxt s60_2009_02_28_233955_t2.txt manage 124 K 2009-03-02 - 10:03 FrankGhigo Antenna tracking, scan 60
s63_2009_03_01_000212_t2.txttxt s63_2009_03_01_000212_t2.txt manage 435 K 2009-03-02 - 10:04 FrankGhigo Antenna tracking, scan 63
scan43I_int173.jpgjpg scan43I_int173.jpg manage 52 K 2009-03-02 - 16:29 FrankGhigo Fig 1: Scan 43 (pass 2) int# 173
scan43I_int173zoom.jpgjpg scan43I_int173zoom.jpg manage 67 K 2009-03-02 - 16:30 FrankGhigo Fig 2: zoom in on Fig 1
scan63I_int171.jpgjpg scan63I_int171.jpg manage 55 K 2009-03-02 - 16:47 FrankGhigo Fig 3 : scan 63 (pass 3) int#171
scan63I_int171zoom.jpgjpg scan63I_int171zoom.jpg manage 75 K 2009-03-02 - 16:48 FrankGhigo Fig 4: zoom in on Fig 3
Topic revision: r12 - 2009-03-26, FrankGhigo
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