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T2874 meteors on moon.

T2874 meteors on the moon

may14

Setup
observing notes
spectra
telescope position

Experiment setup

john matthews looked for meteor flashes on the moon. The experiment used millstone hill and arecibo tracking the moon. Millstone hill would transmit at 440 MHz for about 5 minutes each hour.

The AO setup was:

430 dome receiver
jpl horizon ephemeris file was used to track the moon.
two 10 MHz bands. centered at 433 and 438 MHz
mock spectrometers used in voltage sampling mode

each 10 MHz band was sampled using:
8 bit i,q sampling.
output was done using the pdev file format
see pdev file format for the output file format.

Observing notes

05may14:

he receiver was warm for this run. Tsys was about 130 Kelvins.
Start file: /share/pdata[1,2]/pdev/t2874.20140505.b[0,1]s1g0.00300.pdev
there were 178 files for each band in this scan
All times below are approximate.. except the start time is exact
16:11:13 (ast) start taking data (exact)
16:22:00 on the moon (about file 312)
16:44:xx haystack radar on for awhile (very strong)
16:54:00 cal for 10 seconds (exact time)
17:34:05 start drifting off the moon
17:37 completely off the moon
17:38:xx back on the moon
17:51 millstone radar back on with moon in a null of the beam (to reduce the ao signal)
18:17 tiepos 75 .. was tiepos 77 before
18:40 millstone hill was to come back on.
18:50:09 second scan started (file .00500)
19:07 off the moon
19:09 cal for 10 secs
done..

06may14

17:01:37 started scan file .00000.
17:05:00 cal on 10 seconds
17:xx datataking aborted. arun was copying file off of the datataking machine
17:08:24: start scan .00100.. this ran for the entire run
17:35:xx : millstone transmits
18:08:00 10 sec cal on moon
18:35:xx millstone hill transmits
18:41:24 millstone radar off
18:52:00 stopped telescope tracking moon.. drift off.
18:55:xx drive back onto moon.
19:05:20 millstone radar on (not sure when they turned on)
19:11:xx millstone radar off
19:46:18 hit max za.. moon moving out of beam
19:49:30 10 sec cal
done...

Quick look at the spectra:

The first 50 files of run (300-349 05may14, 100-149 06may14) were used to examine the spectral density.

The processing:

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).

The plots below show the 1.6 second average spectra from the start of the first 50 files:

date	433 MHz band		438 MHz band
	polA	polB	polA	polB
05may14	(.pdf)	(.pdf)	(.pdf)	(.pdf)
06may14	(.pdf)	(.pdf)	(.pdf)	(.pdf)

Notes on the spectra:

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).

processing: x101/14050[5,6]/moonjm.pro

Telescope position.

The telescope position for the two runs was taken from the telescope logfiles. These files have the encoder position information dumped once a second.

Processing:

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

The plots show the telescope and moon ephemeris position for the 2 days (.ps) (.pdf):

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.

processing: x101/140506/moonpos.pro

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