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The Overlap region

The azimuth range of JCMT is from near 0 (North) through 90 (East), 180 (South), 270 (West) back to 360 (North), and on to nearly 450 (East) again. Although the antenna may sit on the same bits of track in quadrants 1 (0 to 90) and 5 (360 to 450), it cannot be assumed that the pointing in these two quadrants is identical.

While processing the inclinometry data, it seemed possible that the data in quadrant 5 may be different from that in quadrant 1. The data below are based on 6 CW datasets taken at the start of 1995 and from 3 datasets (2CW and 1 CCW) taken on 950609 :

                     Ch     1     2     4     5     7     8
   q5 - q1   950121       -0.1   0.2   3.8   1.0   1.5  -0.9 "  
   q5 - q1   950609 CW     0.3   0.8   3.7   1.1   2.9  -1.0 "
   q5 - q1   950609 CCW   -1.9  -0.8  -4.0   0.9   8.9  -1.9 "
For the moment it would appear that for the channels used in the current inclinometry reduction algorithms the overlap effect is small (<1) or negligible, or are due to sporadic, shock-induced effects that will persist until the track joints (or at least the largest ones) are reduced.



Iain Coulson
Wed Mar 12 15:06:27 HST 1997