Table 2.2 The distribution of guiding modes (hours)
SI	Internals   Earth Calib	  Gyro   Coarse track   Fine lock   Total
WFPC2	   18.667	  0.236  7.860	  	0.139	  113.382 140.283
FOC	    0.500	  0.000	 0.000	  	0.000	   17.949  18.449
FOS	    4.564   	  0.000	 0.000	  	0.000	   35.200  39.764
HRS	   10.322	  0.000	 1.333	  	0.000	   22.328  33.983
FGS	    0.000	  0.000	 0.000	  	0.000	    0.065   0.065
Total	   34.053	  0.236	 9.193	  	0.139	  188.924 232.545
Pctg	    14.64	   0.10	  3.95	  	 0.06	    81.24  100.00