nereus.023.log

Asteroid 4660 Nereus

2002 January 23

Updated: 2008 March 19

=========================================================

Schedule and SNR Calculation

                                                    Duration  Rotation
Jan      UTC         PST     RA   Dec  AU    RunSNR    (h)      (&deg;)    
15    1730-2205   0930-1405  321  -1  0.036    100    4.58      109
18    1645-0005   0845-1605  308  -6  0.031    170    7.33      175
19    1630-2335   0830-1535  303  -8  0.030    190    7.08      169
20    1635-2300   0835-1500  298 -10  0.029    200    6.42      153
22    1530-2005   0730-1205  286 -13  0.029    210    4.58      109
23    1505-1950   0705-1150  280 -15  0.029    200    4.75      113
24    1445-1730   0645-0930  274 -16  0.030    190    2.75       66
25    1425-1855   0625-1055  268 -17  0.031    170    4.50      107
26    1405-1915   0605-1115  263 -18  0.032    150    5.17      123
27    1345-1910   0545-1110  258 -19  0.033    120    5.42      129
29    1315-1830   0515-1030  250 -20  0.037     88    5.25      125

=========================================================

UNCERTAINTIES
  With 282 optical observations spanning 30-SEP-1981 to 4-JAN-2002
5 delay and 2 Doppler, 4660 Nereus solution #30 was computed. 3-sigma
X-band uncertainties are shown below. Files have been updated
at Goldstone and Arecibo.

   Note TPM prediction error is one of the uncalibrated error 
sources not included in these uncertainty predictions. This is why 
Doppler error is sometimes replaced by "<1.000" Hz when it gets
very small. Here I left it.

      DATE          Pointing  X-band Dop     Delay  
                      (")         Hz         (sec)  
-----------------  ---------  ----------  ----------
 8-JAN-2002 00:00      1.331       0.178    0.000040
10-JAN-2002 00:00      1.157       0.130    0.000012
12-JAN-2002 00:00      1.084       0.124    0.000004
14-JAN-2002 00:00      1.227       0.133    0.000013
16-JAN-2002 00:00      1.385       0.157    0.000027
18-JAN-2002 00:00      1.540       0.194    0.000045
20-JAN-2002 00:00      1.654       0.240    0.000066
22-JAN-2002 00:00      1.691       0.283    0.000089
24-JAN-2002 00:00      1.647       0.315    0.000110
26-JAN-2002 00:00      1.536       0.330    0.000127
28-JAN-2002 00:00      1.408       0.328    0.000138

=========================================================

Pointing macro for January 23
                                                  TX Offsets    
Date (UTC)   DOY  hhmmss    RA      Dec   Macro  LHA      Dec    RTT  OSOD      
2002 01 23   023  150000 280.7541 -14.5250  A                    29.2  26
2002 01 23   023  160000 280.4876 -14.5922  A   0.0021  -0.0006  29.2
2002 01 23   023  170000 280.2184 -14.6581  AB                   29.2
2002 01 23   023  180000 279.9477 -14.7225   B  0.0022  -0.0005  29.2
2002 01 23   023  190000 279.6769 -14.7853   BC                  29.2
2002 01 23   023  200000 279.4073 -14.8465    C 0.0022  -0.0005  29.2
2002 01 23   023  210000 279.1401 -14.9063    C                  29.3

PRDX.OUT.s36
TRANSMITTER: STATION #14,     RECEIVER: STATION #14
RECEIVER    U.T.         RANGE         DOPPLER      LHA      DEC      RA      EL     
 2002 JAN 23 15:00     29.1663275806   -22064.489 310.1256 -14.5249 280.754  21.284
 2002 JAN 23 15:10     29.1679042499   -22928.438 312.6767 -14.5362 280.710  22.904 
 2002 JAN 23 15:20     29.1695425716   -23823.345 315.2278 -14.5475 280.666  24.478 
 2002 JAN 23 15:30     29.1712446631   -24747.900 317.7791 -14.5587 280.621  26.000 
 2002 JAN 23 15:40     29.1730125620   -25700.734 320.3304 -14.5699 280.577  27.468 
 2002 JAN 23 15:50     29.1748481973   -26680.423 322.8818 -14.5810 280.532  28.876 
 2002 JAN 23 16:00     29.1767534034   -27685.486 325.4333 -14.5921 280.488  30.221 
 2002 JAN 23 16:10     29.1787298990   -28714.396 327.9848 -14.6032 280.443  31.498 
 2002 JAN 23 16:20     29.1807793038   -29765.573 330.5365 -14.6142 280.398  32.702 
 2002 JAN 23 16:30     29.1829031257   -30837.397 333.0882 -14.6252 280.353  33.829 
 2002 JAN 23 16:40     29.1851027503   -31928.205 335.6399 -14.6362 280.308  34.873 
 2002 JAN 23 16:50     29.1873794456   -33036.295 338.1917 -14.6471 280.263  35.830 
 2002 JAN 23 17:00     29.1897343690   -34159.931 340.7436 -14.6580 280.218  36.695 
 2002 JAN 23 17:10     29.1921685420   -35297.346 343.2954 -14.6688 280.173  37.463 
 2002 JAN 23 17:20     29.1946828742   -36446.746 345.8474 -14.6796 280.128  38.130 
 2002 JAN 23 17:30     29.1972781389   -37606.312 348.3993 -14.6904 280.083  38.692 
 2002 JAN 23 17:40     29.1999549808   -38774.205 350.9513 -14.7011 280.038  39.145 
 2002 JAN 23 17:50     29.2027139256   -39948.571 353.5033 -14.7117 279.993  39.486 
 2002 JAN 23 18:00     29.2055553582   -41127.540 356.0553 -14.7224 279.948  39.712 
 2002 JAN 23 18:10     29.2084795319   -42309.234 358.6073 -14.7329 279.903  39.824 
 2002 JAN 23 18:20     29.2114865787   -43491.771   1.1593 -14.7435 279.857  39.819 
 2002 JAN 23 18:30     29.2145764848   -44673.266   3.7113 -14.7540 279.812  39.697 
 2002 JAN 23 18:40     29.2177491180   -45851.836   6.2633 -14.7644 279.767  39.460 
 2002 JAN 23 18:50     29.2210042005   -47025.605   8.8152 -14.7748 279.722  39.109 
 2002 JAN 23 19:00     29.2243413372   -48192.705  11.3672 -14.7852 279.677  38.646 
 2002 JAN 23 19:10     29.2277599887   -49351.283  13.9191 -14.7955 279.632  38.075 
 2002 JAN 23 19:20     29.2312594966   -50499.502  16.4709 -14.8058 279.587  37.399 
 2002 JAN 23 19:30     29.2348390745   -51635.548  19.0227 -14.8160 279.542  36.622 
 2002 JAN 23 19:40     29.2384977991   -52757.627  21.5745 -14.8262 279.497  35.748 
 2002 JAN 23 19:50     29.2422346365   -53863.978  24.1262 -14.8363 279.452  34.783 

=========================================================

BEGIN ELECTRONIC LOG

Benner, Ostro, & Giorgini at JPL
Kern, Smith, Franck, and Choate at Goldstone


Start with solution 36

TX Power =  xxx kW 

 TX  polarization             RCP
 RCV polarization             1=RCP=SC=  K at zenith   K on point at 1739 UTC
                              2=LCP=OC=  K at zenith   K on point
Precal boresight: (at about 1500) (el 21, az 127)
ax +18 mdeg
el -17 mdeg
Source:
az 132
el 17
Those are large corrections.  Yikes!  Must be in a bad part of the sky.
                   

Starting CW setup:
TX polarization           RCP
RCV polarization          LCP
Frequencies:              2
Dwell:                    10 seconds 
Bandwidth:                2000 Hz
Sampling interval:        5000 x 0.1 usec  
VME FFT for PSD files:    4096 for 0.48828-Hz resolution

I called out at about 14:30 to see how things were going.  Precal was going
smoothly.  A guy from Compaq came out yesterday afternoon and replaced a card
and that has fixed the problem we were having.  Carl said that it was a hardware
failure so we were lucky to get as much out of the vax in recent days as we did.


1.0 us x 3.0 Hz setup
---------------------
(code=127, FFT=64, single-pol'n) 
_______________________________________________________________________
 Setup        Baud        RP         1-acc 1-acc      
            usec   m      usec        band   res    acc  band     res 
JX1XS010   1.000  150     127.0     7874.0 123.0     41   192     3.0 
txoff = +30 Hz (= +10 Doppler bins or bin 32+10=42)
loopback should be in gate 13.

I called again at about 1535 as they were setting up 1.0 us.  Carl said 
that the cw echo appeared well centered on zero Hz and that it was about 2 Hz
wide.  The 1.0 us echo TE came in at gate 11, so the echo is one-two gates
early.



1/8 us x 1/8 Hz
---------------
(code=127, FFT=256, single-pol'n) 
 Setup        Baud        RP         1-acc 1-acc      
            usec   m      usec        band   res    acc  band     res 
JX1XS001   0.125   18.75   15.875  62992.1 246.1   1970    32     0.1249
txoff = +8 Hz
CLT = gate 34


********************************************************************
2008 March 19: acc = 1970 is WRONG.  We used 1968 so res = 0.1250 Hz
********************************************************************


1815: There were several faxes when I got into JPL.  The echo went through
an "end-on" phase at roughly 16:00.  One hour later the echo was asymmetric
with more power at positive freqs.  At 17:00 the visible range extent was
at least 15 gates with hints of weak returns out to about 20 gates.

1820: Spoke with Joel.  They just switched macros and did a boresight:
ax +21 mdeg
el -12 mdeg
really close to asteroid.  (1820 UT: target within a few deg of source)
The corrections are enormous again.  We're probably losing a lot of the signal
due to pointing errors.  That may affect the CW results too.  Joel mentioned
that yesterday's boresight corrections were similar so those CW results could
also suffer.  

The LE in the 1/8 us images at 17:00 was at gate 6.  It's my hope that the 
asteroid will rotate into a "broadside" phase by the end of the track.  I'll
estimate a range from that phase when it should be easier to locate the COM.

1934: Latest fax shows the LE is in gate 14, so it moved by +10 gates 
between about 15:50 and 18:50.  This means that the COM is approaching
the ephemeris range gate (34).  We need a new ephemeris for the next track.

1951: End of the track.  

2006: Spoke with Al.  This was an excellent track.  There were no significant
delays or problems.  We got everything we wanted.  One point of concern, though,
is the pointing model: the boresight corrections today were very large.  Marty
and Randy have been putting pressure on the appropriate people to update
the pointing model.  I asked Al to put a comment on the critique noting that
today's boresight corrections indicate that the model needs to be updated.
I also asked Al to write "Excellent track!" on my behalf on the critique.

Tomorrow's track is short so we're going to do only 5 cw cycles and then go
right to imaging using the new solution that I will produce below.

I need to fix Keith's perl script "vax2rdf" so it uses the correct year.  
The current version tags the imaging data with "1998."

2116: There's weak interference in the summed image from file 4 in row 9
(one-based counting).  I saw similar interference a couple of days ago.
There's more in the same row in file 9.  The interference appears as a string
of a broken string of 1-2 sigma pixels as a function of Doppler
frequency.  I checked all the files: those are the only ones that have the
noise.

2238: I made a 15-panel movie of today's images.  They show the asteroid
rotating from an "end-on" phase to a "broadside" phase over about 4 hours,
so the rotation period is close to 16 hours.
Nereus has a prominent facet that is visible over tens of degrees of rotation 
phase.  In one panel the LE is flat and is about 1 Hz wide.  There's clearly
an angularity in the shape adjacent to the facet.  The asteroid is modestly 
elongated: the bandwidths vary from 17 bins (first frame) to 25 bins (last 
frame), so the pole-on elongation is about 1.5.  The maximum bandwidth today
is (25 bins)*(0.125 Hz/bin) = 3.1 Hz.  Earlier in the Goldstone experiment
we got bandwidths of 4-5 Hz so evidently the subradar latitude has moved
away from the equator.  

Update the range
================
I grouped records 19-38 (runs 10-19) from file 10 into one image.  The mid-epoch
is 19:40:00 UTC.  The visible range extent is 10 gates and the TE is in gate 26.
Place the COM in gate 26.  The CLT is in gate 34, so the echo is 26-34 = -8 gates
or 1.0 +/- 0.5 us early.  

PRDX.OUT.s36
TRANSMITTER: STATION #14,     RECEIVER: STATION #14
RECEIVER    U.T.         RANGE         DOPPLER      LHA      DEC      RA      EL     
 2002 JAN 23 19:40     29.2384977991   -52757.627  21.5745 -14.8262 279.497  35.748 
                       -0.000001 +/- 0.5 us
                       ------------
                       29.238497 +/- 0.5 us

 DELAY (weight in 10^-6 sec):
  1937 12 02 19:50:00    R 42.590780605 10.000 8560.D6  -14      Reber,G.
  yyyy mm dd HH:MM:SS type obsrvbl(sec) weight frq(Hz) xstn rstn observer...

  2002 01 23 19:40:00    R 29.238497     0.5   8560.D6  -14      Benner, L. A. M.
  Correction of -1.0 us to solution 36 from 1/8 us imaging.  Place COM at TE
  in gate 26.  Visible range extent is 1.25 us; echo is in broadside phase.


osod > add rad

Example DELAY or DOPPLER input (time is U.T.C.) --
 DELAY (weight in 10^-6 sec):
  1937 12 02 19:50:00    R 42.590780605 10.000 8560.D6  -14      Reber,G.
  yyyy mm dd HH:MM:SS type obsrvbl(sec) weight frq(Hz) xstn rstn observer...

 DOPPLER (weight in Hertz)  :
  1937 11 27 22:20:00    P -540576.10D0 1.0000 8560.D6  -14  -13 Reber,G.
  yyyy mm dd HH:MM:SS type obsrvabl(Hz) weight frq(Hz) xstn rstn observer...

: 2002 01 23 19:40:00    R 29.238497     0.5   8560.D6  -14      Benner, L. A. M.

Enter up to two 78-character comment lines one record) --
: Correction of -1.0 us to solution 36 from 1/8 us imaging.  Place COM at TE
: in gate 26.  Visible range extent is 1.25 us; echo is in broadside phase.

Observation being processed:
  2002  1 23 19:40:00
ADDFILE report:   1 record added  

osod > cmod 36
 
 USERFILE  contained  323 observation(s)
 ADDFILE   contained   12 observation(s)
 MERGEFILE contains   335 observation(s)
 

CMOD varlist over-ride
  ISOLN    = 36

Pass 1 integration step:
 2444896.826  1981 Oct 19.326  -1.13444

Pass 2 integration step:
 2444949.411  1981 Dec 10.911  -2.67323

^L                 Observations, Residuals and Residual Differences  -  Pass 2
                      Observation        Obs         J2000 Residuals           Sigmas    Res. Differences
     Date(UTC)       R.A.      Dec.      Code  R.A.cosD     Dec.      RSS     R.A. Dec  Predicted-2nd Pass
AR2002 123.819444 194000     29.238497   -14          Delay         -0.109    0.500        0.000
AR2002 119.729167 173000  30.285628834   -14          Delay          0.286    0.500        0.000
AR2002 119.000000  00000   31.06051265   -14          Delay         -0.040    0.500        0.000
AR2002 118.833333 200000    31.2442756   -14          Delay          0.014    0.500        0.000
AR2002 115.770833 183000     36.122088   -14          Delay         -0.862    1.000        0.000
AR2002 111.775000 183600   44.91829868    -1          Delay          0.346    1.500        0.000
AP2002 111.770833 183000      68417.78    -1          Doppler       -0.043    0.200        0.000
AR2002 110.818750 193900    47.2799725    -1          Delay          0.129    1.500        0.000
AR2002 1 9.781944 184600     49.916029    -1          Delay         -0.206    4.000        0.000
AC2002 1 4.761740 225833.50 +063027.5    113    -0.356     0.087     0.367    1.0  1.0     0.000     0.000
AC2002 1 4.760570 225833.88 +063028.4    113     0.352    -0.416     0.545    1.0  1.0    -0.001     0.000
AC2002 1 4.759390 225834.21 +063030.1    113     0.269    -0.131     0.299    1.0  1.0    -0.001     0.000
AC2002 1 4.758210 225834.53 +063031.7    113     0.034     0.055     0.064    1.0  1.0    -0.001     0.000
AC2002 1 4.757030 225834.89 +063033.2    113     0.392     0.141     0.416    1.0  1.0    -0.001     0.000
AC2002 1 2.727620 230630.90 +070508.6    151     0.399     0.019     0.400    1.0  1.0     0.000     0.000
AC2002 1 2.725430 230631.43 +070510.6    151     0.330    -0.009     0.330    1.0  1.0    -0.001     0.000
AC2002 1 2.723080 230631.98 +070512.7    151    -0.031    -0.083     0.089    1.0  1.0    -0.001     0.000
AC2002 1 2.720080 230632.72 +070515.8    151     0.065     0.245     0.253    1.0  1.0    -0.001     0.000
AC20011230.730080 231542.10 +074247.7    118    -0.548    -0.479     0.728    1.0  1.0     0.000     0.000
AC20011230.713770 231545.16 +074258.4    118    -0.687    -0.534     0.870    1.0  1.0     0.000     0.000
AC20011230.712530 231545.40 +074259.5    118    -0.600    -0.247     0.649    1.0  1.0     0.000     0.000
AC20011225.103730 232740.18 +082752.3    691    -0.123    -0.234     0.264    1.0  1.0     0.000     0.000
AC20011225.088500 232742.21 +082758.2    691    -0.161    -0.313     0.352    1.0  1.0     0.000     0.000
AC20011225.073990 232744.16 +082803.7    691    -0.193    -0.409     0.452    1.0  1.0     0.000     0.000
AR20011220.953472 225300   103.2425114    -1          Delay         -0.288    4.000        0.000
AP20011218.903472 214100       69201.3    -1          Doppler       -0.109    0.200        0.000
AR20011218.903472 214100    108.380755    -1          Delay          2.465   10.000        0.000

Residuals look good.  Residuals for one of the earlier Goldstone ranges
is up near the 1-sigma level.  

 Object: Asteroid 4660 Nereus
 Ref. Solution:  
 Producer: OSOD/Goldstone
 Planetary Ephemeris: DE405
 Small Body Ephemeris: SB405-CPV-2
 No. Observations:   294
 Observation Arc:  1981 Sep 30 - 2002 Jan 23

 ---- Optical Residuals ----      RA        Dec      Total
 Maximum Residual Difference     0.006     0.002
 Mean                            0.005     0.069     0.069
 Maximum weighted residual                           2.253  at 19820323.231810
 RMS, unweighted                 0.575     0.499     0.538
 RMS, weighted                                       0.538
 Normalized RMS                                      0.538
 No. optical observations:   282

 ----- Radar Residuals -----     Delay   Doppler   Radar+Optical
 Maximum Residual Difference     0.000     0.000
 Normalized RMS                  0.354     0.414        0.535
 No. Delay, Doppler Obs.:  10,  2

 TPM File:  Last Datum 2002 Jan 11  Predicts To 2002 Mar 24

osod > iter 36
 
 USERFILE  contained  323 observation(s)
 ADDFILE   contained   12 observation(s)
 MERGEFILE contains   335 observation(s)
 

CMOD varlist over-ride
  SAVSOL   = T
  ISOLN    = 36

Pass 1 integration step:
 2444896.826  1981 Oct 19.326  -1.13444

Pass 2 integration step:
 2444949.411  1981 Dec 10.911  -2.67323
 
osod > iter 37
 
 USERFILE  contained  323 observation(s)
 ADDFILE   contained   12 observation(s)
 MERGEFILE contains   335 observation(s)
 

CMOD varlist over-ride
  SAVSOL   = T
  ISOLN    = 37

Pass 1 integration step:
 2444957.415  1981 Dec 18.915  -1.06940

Pass 2 integration step:
 2444933.658  1981 Nov 25.158  -1.29271

osod > eph 38

EPHGEN varlist over-ride
  ISOLN   =  38

Integrating back to TSTRT:
 2452306.500  2002 Jan 32.000  -0.00024

Forward integration step:
 2452279.000  2002 Jan  4.500   0.00024
 
osod > pred
 
Computing Doppler/delay predicts. Standby ...
Scanning output ...
 
osod > 



---------------------------------------------------------------------------

 DELAY (weight in 10^-6 sec):
  1937 12 02 19:50:00    R 42.590780605 10.000 8560.D6  -14      Reber,G.
  yyyy mm dd HH:MM:SS type obsrvbl(sec) weight frq(Hz) xstn rstn observer...


 DOPPLER (weight in Hertz)  :
  1937 11 27 22:20:00    P -540576.10D0 1.0000 8560.D6  -14  -13 Reber,G.
  yyyy mm dd HH:MM:SS type obsrvabl(Hz) weight frq(Hz) xstn rstn observer...

===================================================================================================

MASTERLOG
===================================================================================================
                                             RCV      
file         setup                  runs start -stop    osod    OFFSET    TX Poln    
---------------------------------------------------------------------------------------------------
PSD02023RCP.4660_Nereus, VOLT02023RCP.4660_Nereus
          CW 2 kHz 4096 FFT          10  150544-151515   36       none     RCP
PSD02023LCP.4660_Nereus, VOLT02023LCP.4660_Nereus
          CW 2 kHz 4096 FFT          10  151648-152618   36       none     RCP
ne02303      1 us x 3.0 Hz  127 code  5  153745-154225   36       +30      RCP      
ne02304    1/8 us x 1/8 Hz  127 code 50  154532-163719   36        +8      RCP         
ne02305    1/8 us x 1/8 Hz  127 code 50  164050-173327   36        +8      RCP         
ne02306a   1/8 us x 1/8 Hz  127 code 18  174108-175937   36        +8      RCP         
ne02309    1/8 us x 1/8 Hz  127 code 50  182901-192124   36        +8      RCP      
ne02310    1/8 us x 1/8 Hz  127 code 24  192534-195008   36        +8      RCP      

===================================================================================================

ASTROMETRY
==========

  2002 01 23 19:40:00    R 29.238497     0.5   8560.D6  -14      Benner, L. A. M.
  Correction of -1.0 us to solution 36 from 1/8 us imaging.  Place COM at TE
  in gate 26.  Visible range extent is 1.25 us; echo is in broadside phase.

===================================================================================================

PROBLEMS
========
1. Boresight corrections are very large.  Pointing model needs to be updated.


Things to do after the track
============================
1. ftp cw data from the VME -> intruder            	==> done
2. scp cw data from intruder -> JPL                     ==> done
3. write protect cw data on reason                      ==> done
3. ftp ranging data from the VAX -> intruder            ==> done
4. convert vax *.dat files to rdf files			==> done
5  scp rdf ranging data from intruder -> JPL 	        ==> done
6. write protect ranging data on reason   		==> done
7. ftp tx/rcv logs to intruder                          ==> done
8. scp tx/rcv logs from intruder to JPL	                ==> done
9. write protect tx/rcv, ops, & cal log files at JPL    ==> done
10.update planning page w/astrometry        		==> 
11.draft a log file for the next track			==> 
12.critique 						==> done
13.get the data package				        ==> 
14.back up the data -> exabyte tape & write protect it	==> in progress: cdroms
15.organize hardcopies in the notebook 			==> done
16.scp observational log -> JPL and write protect it	==> done
17.e-mail brief summary of results -> co-authors        ==> 
18.e-mail brief summary -> Ralph & Larry                ==> 
19.do a preliminary reduction of the cw data            ==> 
20.reduce the imaging data                              ==> done
21.scp new orbital solutions from intruder -> JPL       ==> done
22.Contact optical observers (Pravec, Hicks, Buie...)	==> 
23.draft an imaging script for the next track		==> 
24.update the masterlog                                 ==> done