Experiment setup

• alfa receiver (rotation angle fixed at 0deg)
• Alfa notes:
• beam 3b was turned off .. it was dead
• beam 6b has been bad.. but it think it had recovered (check cal deflection).
  
• jpl horizon ephemeris file was used to track the moon.
  
• one 6.4 MHz band  centered at 1415 Mhz
  
• mock spectrometers used in voltage sampling mode
• the 6.4  MHz band was complex sampled  and recorded 16 bits (both pols)
  
• a +10Mhz analog offset followed by a -10 Mhz digital offset was used to get rid of a/d DC and analog 60 hz.
  
• output was done using the pdev file format
• see pdev file format for the  output file format.
  

Observing  notes

14feb16:

• Start file: /share/pdata[1..7]/pdev/s3039.20160214.b[0..6]s1g0.00000.pdev
• there were 232 files for each alfa beam
  
• All times below are approximate.. except the start time is exact
• wait till on moon.
• adjust power levels for 1 sigma = 15 counts
• most were higher since all gain was removed and still about 15 counts.
  
• 16:49:54  (ast) start taking data (exact)
  
• 16:51:31  high cal turned on (manually)
• 16:5200   high cal off (manually)
• 19:16:00   high cal on .. still on moon
  
• 19:16:30   high cal off
• xxxx          off the moon
  
• 19:29:30    high cal on  (off the moon) (rms probably now has too few counts)
  
• 19:30:30    high cal off
  
• 19:30:xx    done with observation
  

06may14

• start file: /share/pdata[1..7]/pdev/s3039.20160215.b[0..6].s1g0.000000.pdev
• had 3 separate scans
  
• 000 .. 021
• 100 ..172
• 200 .. 342
• Total of 238 files/beam
• Waited till on moon.
• adjust mock power levels. 1 sigma=15 counts
• 17:40:55  started scan file .00000.
• 17:32:00   high cal on for 30 secs
• 17:32:30   high cal off
  
• 17:05:00  cal on 10 seconds
• 17:56:41  started scan file 00100
• 18:48:34  start scan file 00200
• 20:22:00   high cal on for 30 secs (still on moon)
• 20:22:30    high cal off
  
• 20:27:00   high on for 30 secs (off the moon) rms counts probably now too low
• 20:27:30    high cal off
  
• 20:27:xx   done with observation
  

Quick look at the spectra:  

• 2^24 points from the start of each file were processed for the first 50 files of scan 300.
• the 16 million points is about 1.6 seconds of data
• 8k fft's were done (1.2 Khz resolution), power computed and then averaged for the 1.6   seconds
• Each 1.6 sec spectra were normalized to their median value (Tsys).

• Both days:
• rfi in polA looks a lot stronger than that in polB
• rms's on moon were 30 to 40 counts for 1 sigma in the 8 bit digitizer.
• The cal temps are 95.5, 102.6 for polA, polB
• On the oscilloscope we saw rfi with 12 second periods reflected off the moon.
• land base radars (in PR) have 12 second rotation period.
• I've seen ship based radars with 4 second rotation periods.
  
• 05may14:
• moon come into beam during the 12th file : .00011.pdev
• Tsys was about 130 K off the moon.
  
• 06may14
• Tsys was about 80 K off the moon.
  
• file 121, 431.8MHz birdies starts drifting to higher frequency.
• at file 149 it has moved about 1 MHz.
• This may be rfi from the sbn postamp chassis. in the 327 receiver we saw it drift by this amount (more info)
  
• The rfi off the moon looks much stronger in polA than polB (pols are circular).
  
• this may be real or just a difference in Tsys for the 2 pols (when the dewar is warm.. need to check the cals).

Telescope position.

Processing:

• model correction was removed from the az,za encoder values
• the az,za was backcomputed to ra,dec of date.

• Page 1: 05may14:
• Top: RA (of date) vs hour of day (UTC)
• black AO telescope
• red moon ephemeris file
• 2nd: DEC(of date) vs hour of day (UTC)
• black AO telescope
• red moon ephemeris file
• bottom: position error Asecond (great circle)
• Black RaEphm - RaTelescope
• the error was computed as: (radif)*15*3600*cos(declination)
  
• red : decEphm  - DecTel
• The error was computed at: (decDif)*3600
• at 21.6 the telescope tracking was stopped so the moon drifted out of the beam
• . a few minutes later we drove back onto the moon.
• Page 2: 06may14 run.
• at 22.9 the telescope tracking was stopped so the moon drifted out of the beam
• . a few minutes later we drove back onto the moon.

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