The most recently measured value of the 225 GHz optical depth at the CSO is 0.000. This measurement occurred at 19:13 UT. The current time is 19:17 UT.
The most recently measured value of the 350 micron optical depth at the CSO is 1.4. This measurement occurred at 18:57:44 UT on 2008-05-09. With a scaling factor of 24.75, this gives another estimate of optical depth at 225 GHz of 0.057.
If you'd like to see plots of tau vs. time and/or tau cumulative distribution functions by quarter and by month, click here.
For a short explanation of the tau sky monitor instrumentation click here .