10.6. Time required for time estimation

When you make a time estimate HSpot connects with the server at the HSC to pass the information on the AOR and make the calculation of the time required to carry it out. You will need to calculate a duration for all your AORs before proposal submission and every time that the AORs are revised. For PACS and SPIRE the calculation is particularly rapid, especially in photometry mode. On a fast Internet connection time estimation for 100 PACS or SPIRE photometry AORs can be calculated in approximately 20 seconds. Time estimation for the same number of SPIRE PACS Parallel Mode, or PACS or SPIRE spectroscopy AORs will take from 30-40 seconds. Because of the large number of parameters in some HIFI AORs, the calculation is somewhat slower for HIFI: time estimation for 100 HPoint or HMmap AORs will take some 2-3 minutes even if there is no other load on the system; while 100 HScan AORs may take in excess of 5 minutes to time estimate. Even when several users are carrying out time estimation simultaneously and the system is under heavy load, the time required should not increase by more than a factor of about three.

For PACS the time required to run a certain number of time estimates is generally slightly shorter than for similar SPIRE AORs: generally HSpot should carry out from 3 to 6 time estimates per second. HIFI runs somewhat slower due to the large number of parameters to be optimised, but will usually be in the range from 1 to 3 seconds per time estimate, although HIFI Spectral Scans can, in extreme cases, take as much as half a minute to estimate each if a lot of sequencer optimisation is required.

In the hours before a call closure we have noticed that the system load may be so high that time estimation runs extremely slowly. Various protective measures have been put into place to avoid this happening in future call closures, however, if the system watchdog detects excessive load, the HSC reserves the right to switch off time estimation for short periods so that all the system capacity is available for proposal processing. In the unlikely event that this should be necessary, a pop-up will appear warning the user when time estimation is requested. In this case, the time estimation should be deferred, if necessary until after the Call is closed and the proposal should be submitted with the out of date time estimates that are available in the user's HSpot session.