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QUEUE-BASED FLEXIBLE IMPLEMENTATION GUIDELINES
WEATHER GUIDELINESIn order to maximise the productivity of the JCMT, and in particular to ensure that the science performed at the telescope is best suited to the observing conditions, the ITAC has endeavoured to move some way towards flexible scheduling. To facilitate this it has decided to attempt to identify the range of weather conditions within which each programme allocated time should be pursued. The weather categories adopted, in liason with the Director JCMT are as follows:
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| Weather Grade | Definition | CSO Tau | Prime Instrument(s) |
|---|---|---|---|
| 1 | very dry | τ < 0.05 | RxW(D), HARP (>360GHz) |
| 2 | dry | 0.05 < τ < 0.08 | HARP |
| 3 | medium | 0.08 < τ < 0.12 | HARP |
| 4 | wet | 0.12 < τ < 0.2 | HARP, RxA3 |
| 5 | very wet | 0.2 < τ | RxA3 |
To achieve a more realistic match to the weather statistics it has also been decided to formally allocate only a fraction of the actual number of available UK shifts, and only half of that allocated time to proposals requiring very good weather (1-2 weather band). Proposals allocated time will therefore, where possible, be placed within somewhat expanded time slots in the schedule. During these blocks, proposers who have been allocated time will be permitted to spend all of the time during which the weather coincides with their assigned weather band, up to a maximum time equal to their actual formal allocation. In return for this increased chance of completing/advancing their programmes, scheduled observers will also be expected NOT to pursue their programme when the weather is either better or worse than their assigned band (or if by good luck they get their full allocation of appropriate weather before the block is finished) and instead to implement an appropriate proposal from the appropriate-weather backup/flex queue as directed by the JCMT scheduler (basically the highest ranked proposal on the appropriate queue for which targets within the appropriate RA range are available).
Backup queues have thus been created, and many applicants who have not been awarded a formal allocation of time will find that their proposals have been placed on these queues, especially if they do not require very dry weather (and were not sufficiently highly rated for a formal allocation). These queues are:
1. The Grade-3 weather backup queue - `easy' SCUBA work and heterodyne observing at moderate frquencies
2. The Grade 4-5 weather backup queue - basically A-band work
EXAMPLE OF HOW THIS IS MEANT TO WORK IN PRACTICE
Suppose you have been awarded 2 shifts of grade 1-2 weather. Where possible this will be scheduled within a 4 shift block, and if the first 2 nights were dryer than grade 3 weather you would be able to pursue your programme. However, if the weather deteriorated to grade 3 weather on night 3 you would, according to the rules of flexible observing, be expected to implement the highest rated appropriate proposal from the Grade-3 weather backup queue. If on night 4 the weather deteriorated further to grade 4 conditions, you would be expected to implement the highest rated appropriate proposal from the Grade 4-5 weather backup queue, etc.All applicants with formally allocated time and all applicants with backup time will be notified of these facts via e-mail from the JCMT Scheduler shortly after each ITAC meeting. Observing templates are required to be submitted for ALL these applications by the end of the first month of each semester - whether applicants intend to come to the telescope or not (because it is useful for a template for every PATT-approved programme to be held at the JACH to facilitate flexible observing). Starting semester 02B, all SCUBA projects will be required to use observing plans prepared with the new Observing Tool (OT). Heterodyne projects must still use observing templates as in previous semesters.
NOTE FOR APPLICANTS ALLOCATED SCHEDULED TIME
If you have been awarded a formal allocation, then it is your responsibility to make sure that someone will be here to cover your shift(s), either by yourself or one of your collaborators, or by arranging for another observer to stay on. The JAC does not, alas, have sufficient staff to provide service observing except on an emergency basis, but we will be happy to help you to find someone. Note that even if, in the flexible observing scheme, your project should be completed before you arrive for your scheduled run, you will still need to provide an observer for those shifts.The ITAC would like to encourage you to travel to the telescope and staff the whole of your expanded run. In return for this flexible block the ITAC expects disciplined observing, in terms of moving to the backup queues if appropriate. The ITAC, and national TAGs, will not look kindly on observers who continue to pursue their own programmes in inappropriate conditions, and, to encourage a disciplined attitude, the UK TAG has decided to `star' all proposals requiring very good (1-2) weather ('starred' applications are indicated on the web schedule by having a '*' placed after the PATT number). This star acknowledges that programmes requiring 1-2 weather are on average least likely to obtain the necessary full quota of appropriate weather to be completed, and indicates that applicants can have a reasonable expectation that that payback time will be made available in the following semester, always subject to final approval of their case by the UK TAG.
NOTE FOR APPLICANTS ALLOCATED TIME ON THE BACKUP QUEUES
With the reduction in the number of shifts formally allocated for the UK, proposers who have their proposals placed on these backup queues should have a somewhat higher expectation that their proposals will be implemented than was perhaps the case in previous semesters. You are encouraged to complete templates for your backup proposals as soon as possible (before the end of the first month of each semester), to enable your proposal to be implemented whenever a suitable situation should occur. The ITAC's intention is that many of these backup programmes should be completed or at least significantly advanced during the coming semester.
NOTE FOR APPLICANTS NOT ALLOCATED TIME
The ITAC would like to encourage you to be patient if you have not been awarded time. The long-awaited advent of SCUBA, combined with the TAG's efforts to move towards flexible scheduling have resulted in high-frequency (good weather) time being oversubscribed by a factor above or about 3 each semester. By allocating sensible amounts of time to the most highly rated proposals at this stage, the ITAC aims to get some major new programmes completed fairly rapidly which should clear the way for other programmes in future semesters.
NOTE FOR ALL HETERODYNE APPLICANTS
The ITAC would also like to assure heterodyne applicants that any perceived SCUBA bias in the TAG allocations is an illusion. All proposals are assessed together for scientific merit, and heterodyne proposals which are sufficiently highly ranked are given a formal allocation. Heterodyne proposals inevitably make up a large fraction of the proposals in the backup queues because they often provide the only sensible use of low-frequency weather. Indeed the ITAC wish to encourage MORE A-band heterodyne proposals. Since all heterodyne proposals in the backup queues have by definition failed to achieve a sufficiently high grade to merit a formal allocation, their presence on the backup queues should be regarded as a bonus. Most SCUBA proposals which fail to make the grade for a formal allocation simply get no time at all, simply because SCUBA proposals are rarely suitable for low frequency backup work.