The following table the observed filter optical depths measured at
the listed line.  There are two filters of each type, the first has
a nominal tau=2, and the second tau=4.  The uncertainty in these
numbers is roughly 0.05.



Line     E(keV)     fid   tau        fid   tau
CuL       .9297     18    2.95       18    3.86
CuK      8.048      15    2.11       15    4.38
NiL       .852      16    2.23       16    7.04
NiK      7.478      14    2.27       14    4.01
ZnL      1.012      19    1.50       19    3.11
ZnK      8.631      17    1.83       17    3.88
ZrL      2.042      20    1.49       20    3.73
AgL      2.982      23    1.44       23    3.03
MoL      2.293      22    2.69       22    5.63
SnL      3.441      24    1.63       24    3.38
WL       8.397      17    1.96       17    4.21
CoK      6.925      12    1.64       12    3.33
CrK      5.415       9    2.16        9    3.72
FeL       .705      13    2.26       13    4.28
FeK      6.399      12    1.86       12    3.91
TiK      4.509       7    2.03        7    3.80
TiL       .452       4    --          4    --
MgK      1.254       5    2.42        5    4.20
AlK      1.489       6    1.93        6    3.71
CK        .277       3    2.13        3    4.40
BK        .183      31    1.63       31    3.37
BeK       .109      30    --         30    --