Analysis

Here is a

Figure 3.31: Graph of about one month of data in December 2006 plotting black TempSensor A:black and TempSensor F:red. Note the quicker response of the secondary mirror sensor.

Table 3.24: Chart of the average temperature and standard deviations of the sensors as well as the METS OAT sensor over 1 month.

Sensor	Mean	Std.Dev
A	4.41	3.7
C	4.87	3.7
E	4.15	4.1
F	3.96	4.2
H	6.96	4.1
oat	5.15	5.6

Note the lower standard deviations of A and C rather than the ones closer to air temperature such as F or OAT. There is a few a lag of a few hours. Also the H sensor seems to be anomalously high.

The B, D and G sensors seem to be DOA.

1/3/2007: The D temperature sensor seems to have died.

Conclusion: recommend using the A sensor for determining the focus position. In fact it might be desirable to integrate the A reading and damp it a bit, but this is probably not necessary.

Figure 3.32: Photo of all the hockey pucks on the East side of the telescope.

Figure 3.33: Photo of Temperature Sensor A on the lower truss at the North.