NRAO Home  >  Green Bank  >  Astronomers  >  GBT Observing Schedules  > Dynamic Scheduling Description

High frequency observing requires good weather. To most efficiently use observing time it is important to observe at high frequency during appropriately good weather conditions and observe at low frequencies during bad weather whenever possible. This requires dynamic scheduling. There are insufficient software tools in place to implement a true dynamic scheduling scheme. Until these tools are available we have attempted to implement a partial or pseudo dynamic scheme. The procedure to be followed is outlined in the following steps.

• Low frequency observations will be scheduled as backup (secondary) projects in parallel with scheduled high frequency observations whenever possible. The latter are indicated by by a plus sign (+) on the graphics observing schedule and the former are listed in the daily details as well as in their own graphics version.

• The decision maker will be the primary project observer. This should be discussed and communicated with the GBT scheduler (at the very least) during normal work days and the operator on weekends and holidays. If desired other staff may be consulted as well.

• The decision will be made by noon each day for all observing for the next 24 hours starting at 17:00 Eastern time on the day of the decision. The decision on weekend days and holidays will be made by noon of each day also. This will allow for more flexibility in adapting to changing weather conditions during weekends and holidays.

• The decision will be a go or no go for the primary project with no "maybes".

• On normal work days the scheduler, or his designee in his absence, will be responsible for the communication of this decision to the secondary project observer and the operations staff. The form of the communication will be "in person" (whenever possible) to the secondary project observer and the operator (when in the control room) with a follow up email to gbtops and gbt. On weekends and holidays: The operator will be the focal point of communications. The Observer for the high frequency project MUST make his decision by noon and communicate it directly to the operator. The low frequency (secondary project) observer must contact the operator for the decision.

• Last minute changes in the decision (ie to give the high frequency observing time to the low frequency observing program) after the basic decision has already been made would only be permitted by the primary project observer without a 'penalty' when very unusual and unavoidable circumstances arose (for example the receiver broke and could no longer be used). In the case when the primary project observer decided to proceed with his observations in marginal weather he could not change his mind after he started his observing. If he did all of this scheduled observing time would be charged to his allotment and could not be rescheduled without reapplying through the normal proposal process (his proposal would have to be reviewed and approved before rescheduling).

• We will schedule the visitors for a primary project to be on site for an appropriate period of say one week (whatever seems reasonable or possible for the primary observer - longer may be possible if he has graduate students who could stay longer) and schedule their time in two blocks (2x their allotted time) during this one week. The secondary project would be one from our local (GB or CV) staff or possibly another visitor (such as a graduate student) who could stay for a longer period (eg two weeks). If there was no genuine "good weather" period for the primary observer during his one (?) week stay, their observations would be rescheduled later (probably at least 1.5 - 2 months later or during the next high frequency session) and the observer will have to return at that later time. If the secondary project observer is a visitor it is a little easier to guarantee fulfilling his observing requirements since the primary projects would be scheduled for twice their allotted time. It does however mean that good high frequency weather time may go to low frequency observing.

Although this scheme has many shortcomings it seems the best compromise for the present. The procedures will be constantly under review. (last updated - 08/27/03)