6.2 Determination of the Effective Exposure Times

The effective exposure times for the 1983-1985 Epoch ITFs were derived by Imhoff (1984b and 1986), by De La Peña and Coulter (1996) for the 1992 Epoch LWP ITF, and by De La Peña for the LWR ITFs. During the creation of the 1983-1985 ITFs in their own geometric space for the NEWSIPS system, if additional images were deemed usable in contrast to those originally chosen by Imhoff, the effective exposure times were modified to reflect the use of additional images.

Table 6.1 lists the effective exposure times (FN exposure values) for each level of the ITFs used in the Final Archive. These exposure values have been normalized to an arbitrary scale such that the FN associated with the lowest level of an ITF is 0.0.

 

 

ITF SWP LWP LWR ITFA LWR ITFB

Level Epoch 1985 Epoch 1992 Epoch 1983 Epoch 1983

1 0.000 0.000 0.000 0.000

2 32.919 38.750 35.880 35.607

3 67.946 78.737 72.974 72.425

4 104.147 121.868 91.067 89.708

5 131.397 168.958 125.213 125.621

6 166.296 200.756 156.510 162.627

7 223.034 237.941 193.275 198.780

8 269.680 278.107 245.053 254.362

9 340.471 341.073 283.705 288.706

10 408.490 396.582 320.355 325.599

11 473.749 483.497 385.554 401.720

12 575.995 561.518 471.557 490.480