Obs 5688

Summary

Obs 5688 was a difficult obsid to schedule for ACA, and even with hand editing the final catalog was near the limits of acceptability from the ACA review perspective.

We now have the observation data in house and it confirms that this catalog is really about as far as we want to push. Most of the observation was spent on three kalman stars, with a brief period where the OBC was dropping to two kalman stars. The roll bias noise and PCAD attitude error were substantially higher than normal, due to stars dropping in and out of use by the OBC. The good news is that the subsequent maneuver had a nominal one-shot error.

One disturbing issue to note is that the final two guide stars were predicted to have mags 10.40 and 10.56. Both of these are well within the ACA capability. In fact they turned out to be 11.3 and 11.1 mags, respectively.

Data and Plots

The science aspect solution required reprocessing and will use only three stars. With those three stars the solution will still meet requirements but will be poor by our standards.

OBSID: 5688   AXJ1426.9+2334          ACIS-S  SIM Z offset: 0      Grating: NONE     
RA, Dec, Roll (deg):   216.748592    23.586964   142.991060
Dither: ON  Y_amp= 8.0  Z_amp= 8.0  Y_period=1000.0  Z_period= 707.1
BACKSTOP GUIDE_SUMM OR MANVR DOT MAKE_STARS 


MP_TARGQUAT at 2005:100:18:43:16.322 (VCDU count = 12689231)
  Q1,Q2,Q3,Q4: 0.23105556  -0.90140255  -0.23374392  0.28186973
  MANVR: Angle=  28.29 deg  Duration= 1013 sec  Slew err= 30.7 arcsec

MP_STARCAT at 2005:100:18:43:17.965 (VCDU count = 12689237)
----------------------------------------------------------------------------------------
 IDX SLOT        ID  TYPE   SZ  MINMAG    MAG   MAXMAG   YANG   ZANG DIM RES HALFW NOTES
----------------------------------------------------------------------------------------
[ 1]  0           2   FID  8x8   5.797   7.000   8.000   -755  -1727   1   1   25          
[ 2]  1           4   FID  8x8   5.797   7.000   8.000   2158    181   1   1   25          
[ 3]  2           5   FID  8x8   5.797   7.000   8.000  -1808    175   1   1   25          
[ 4]  3   263192752   BOT  6x6   5.797  10.063  11.562   1304    566  20   1  120  a3g3    
[ 5]  4   263198168   BOT  6x6   5.797   8.813  10.312  -2140   2310  16   1  100          
[ 6]  5   263199776   BOT  6x6   5.797  10.130  12.312  -1297    694  20   1  120  a3g3    
[ 7]  6   263201496   BOT  6x6   5.797  10.403  12.625   1101   -733  20   1  120  a3g4    
[ 8]  7   263198776   BOT  6x6   5.797  10.563  12.125   2002    654  20   1  120  a3g4    
[ 9]  0   263198808   ACQ  6x6   5.797  10.678  12.188   -542    413  20   1  120    a3    
[10]  1   263194336   ACQ  8x8   5.797  10.776  12.281     93    -54  20   1  120    a3    
[11]  2   263192848   ACQ  8x8   5.797  10.415  11.922     56  -1103  20   1  120    aX    


>> WARNING: Search spoiler. [ 7]-  263198816: Y,Z,Radial,Mag seps:  60 122 136 -0.1
>> WARNING: Magnitude. [10]: 10.776
>> WARNING: Readout Size. [10]: 8x8 Should be 6x6
>> WARNING: Readout Size. [11]: 8x8 Should be 6x6
>> WARNING: Magnitude. [ 7]: 10.403
>> WARNING: Magnitude. [ 8]: 10.563
>> WARNING: Magnitude. [ 9]: 10.678
>> WARNING: Magnitude. [11]: 10.415


Acquisition Figure of Merit : -5.06
Acquisition Stars Expected  : 5.82





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Last modified:12/27/13

Engineering plots

Locked on 3 kalman stars for the majority of the time, with one interval of 2



Pitch and Yaw attitude error quite bad



One shot on next manuever was fine



Continued loss and reacquisition of faint stars made the gyro bias unstable