The following rules were agreed by the ING Board at its meeting of May 2000 in Leiden:

1. The key objectives for offering guaranteed observing time are (a) to provide an incentive for groups to take on developing new instruments, (b) to provide fast exploitation and science verification of the new facility, and (c) to provide a reward for the effort invested as an incentive to attract young scientist into the field of astronomical instrumentation.

2. This proposal for guaranteed observing time only considers common-user facility instruments, where the observatory assumes overall responsibility for the instrument after commissioning and formal acceptance, and the instrument is made available to all observers in the UK and NL communities. Visiting instruments and instruments that are only made available to the wider user community for a fixed, short period are discounted from this scheme, as are minor enhancements to existing instruments.

3. The following points present the ground rules for guaranteed observing time for instrument building teams:

• The project scientist of any group delivering a common-user facility instrument to ING is awarded guaranteed observing time on that instrument. The instrument has to fulfil the criteria set by the Observatory, and has formally passed acceptance before guaranteed observing time is granted.
• For externally funded instruments, the team is offered one night for every three nights awarded by the UK and NL Time Allocation Committees to the instrument for the first four semesters following acceptance.
• For internally funded instruments one night is offered for every six nights allocated by the UK and NL Time Allocation Committees for a period of four semesters. This allocation is capped to a maximum of four nights per semester.
• The guaranteed time is awarded to the (principal) Project Scientist. Before granting the time the Project Scientist must present a proposal to the Director describing the scientific programme, including a technical case. In case the Director is not satisfied by the quality of the proposal the telescope time reverts to the TACs.
• The Director may decide to release some of the observing time during the semester of commissioning to promote fast science exploitation. Such early allocation is then deducted from the allocation during subsequent semesters.

4. Internally funded projects use funds earmarked as part of the ING development programme and are formally managed under the control of the Director ING and the ING Board. All other projects are considered externally funded, although the funds could emanate from the funding agencies.

5. Any request for guaranteed observing time falling outside the scope of these guidelines would have to be put forward to the Director and approved by the ING Board.