The Prime levels are updated in a sheet periodically by us .
The link is here- https://docs.google.com/spreadsheet/ccc?key=0Aguuu7T3NhX2dG1YbTQ5RUUxS1ZDM09uVHBuVnpYZkE&pli=1#gid=3
You can also access it through the today page and the link is open to all.
The prime levels are made on the last big auction in the markets and is independent of clock time as measured in hours, minutes or days.
We believe in auction theory that the markets move in the way they want based on buy-sell pressures and is independent of time. It's for this reason we refuse to calibrate the market in minutes or hours.
Coming to the subject of the post, the most important number in the prime levels sheet is PP0 which is the number to get the bias of the market. The market has tilted to the buy side when it moves above pp0 and to the sell side when it moves below.
The levels PR1 and PS1 represent extremes of the current swing and a market which moves beyond these points is known to have changes the swing and is likely to move to PR2 and even PR3 or PS2 or PS3 as the case may be.
As an example today's PR1 in NF is 5642 which the market has to take out to reverse the previous swing down.
Similarly the BNF took out PR1 at 11434 yesterday and promptly moved to PR2 11521 today and may even get to PR3 at 11608 or closer.
These are not absolute numbers but important supporting tools to get the bias of the market right.