This report covers differential pointing between RxWD and RxA during January 2009. The differential pointing performance is measured by pointings with RxA and RxWD consecutively for direct comparison. (All WD observations are taken with channel A with the exception of obs. number #64).

   UT Date    No.    Source    FE       AZ      EL     UAZ     UEL      DAZ     DEL      WD-A
 ----------  ----  ---------  ----     ----    ----   -----   -----    -----   -----   --------
                       
   20090107    3     Uranus    A        227     55     -0.8    7.2   
       "       5        "      WD       232     53      3.1    3.3      3.9     -3.9     5 - 3
       "      19      W3(OH)   WD       359     48      3.8   -3.7      1.0     -4.5    19 - 20
       "      20        "      A        359     48      2.8    0.8
       "      56     IRC10216  A	128	80	1.5   -1.2
       "      59        "      WD	145	82	5.1   -5.3	3.6	-4.1	59 - 56
       "      59        "      WD	145	82	5.1   -5.3	3.7	-4.5	59 - 60
       "      60        "      A	158	83	1.4   -0.8			
       "      64       	"      WDB	183	83	9.8   -6.2	8.4	-5.4	64 - 60
       "      64    	"      WDB	183	83	9.8   -6.2	8.4	-7.8	64 - 65
       "      65    	"      A	193	83	1.4    1.6


   20090112   27     IRC10216  A	84	27     -3.0	5.1			
       "      29        "      WD	86	33	0.6	0.1	3.6	-5.0	29 - 27
       "      29	"      WD	86	33	0.6	0.1	2.7	-6.2	29 - 35
       "      35	"      A	91	46     -2.1	6.3			
       "      		       						
       "      52	"      A	140	81	0.8	2.2			
       "      54	"      WD	162	83	6.3    -3.9	5.5	-6.1	54 - 52
       "      54	"      WD	162	83	6.3    -3.9	6.0	 0.3	54 - 56
       "      56	"      A	189	83	0.1	3.6			
       "      57	"      WD	200	83	5.3    -1.2	5.2	-4.8	57 - 56
       "      57	"      WD	200	83	5.3    -1.2	6.0	-4.7	57 - 59
       "      59	"      A	224	81	-0.7	3.5			
       "      		       						
       "      65	"      A	255	69	0.3	4.3			
       "      66	"      WD	256	67	3.6    -2.2	3.3	-6.5	66 - 65
       "      66	"      WD	256	67	3.6    -2.2	2.5	-6.4	66 - 67
       "      67	"      A	257	66	1.1	4.2			
       "      68	"      WD	259	65	4.2    -1.6	3.1	-5.8	68 - 67
       "      72	"      WD	262	59	4.3	0.6	3.2	-3.6	68 - 72
       "      		       						
       "      80	"      A	270	40	0.1	7.9			
       "      83	"      WD	272	35	-2.8	1.1    -2.9	-6.8	83 - 80



(UZ and UEL are offsets from the model, whilst DAZ and DEL are offsets from the nearest RxA pointing.)
 

The results are displayed below; azimuth on the left and elevation on the right. Where there are 2 possible solutions for daz and del for a single observation, the pairing closet in time was selected. The values derived from channel B have not been included due to the misalignment of the 2 channels on this date.

The single errant point comes from obs. number #83 which is the sole point with a negative value for daz. Inspection of this observation reveals a tenuous pointing fit and as such it can be considered erroneous and is not included in the fitting below.

These plots demonstrate the absence of either azimuth or elevation dependence in the differential pointing of RxWD.

The distributions are best fit by the following expressions:

del=-0.01(el)-4.2
del= 0(az)-5.2
daz= 0.04(el)+0.8
daz=-0.01(az)+6.0