The most recently measured value of the 225 GHz optical depth at the CSO is 0.096. This measurement occurred at 23:34 UT. The current time is 23:47 UT.
The most recently measured value of the 350 micron optical depth at the CSO is 30.9. This measurement occurred at 23:21:02 UT on 2008-07-24. With a scaling factor of 24.75, this gives another estimate of optical depth at 225 GHz of 1.248.
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 .