Reactive & Priority Z Time

Reactive Time Programme

Researchers can apply for LT observations in a Reactive Time mode, outside of the usual semester-based rounds. The intention is to provide rapid (a few days) access to LT observations.

Time on the LT is allocated by several Telescope Allocation Groups (TAGs). Not all have chosen to use this reactive mechanism; the TAGs currently accepting applications are listed on the submission form. If you do not fall into any of the listed categories, please contact the LT Support Astronomer to discuss your project — we may still be able to accommodate your request.

Rules of Use

Proposals are accepted in two broad categories:

The reactive programme increases the flexibility of the time-allocation process and takes full advantage of the robotic nature of the LT. It complements the normal PATT and JMU process, so it is unlikely that time will be awarded to a proposal that could have gone through the traditional semester-based route. We generally do not award reactive time to PATT, CAT or JMU proposals that have simply run out of time in an existing semester — in that case, please contact the LT Support Astronomer rather than request 'top-up' time.

Proposals can be submitted at any time and will be assessed by the appropriate TAG (or a subset of it) as soon as possible after receipt. If accepted, the project is given a rank in the current queue based on its science rating relative to existing programmes and its urgency. Whether and when the observations are completed depends on this rank and cannot be guaranteed, but is likely to be a minimum of one working day.

Applications should be made using only the Phase 1 proposal form. To help us process your proposal quickly, keep the scientific and technical cases clear and concise (they are entered as plain text). By default, reactive allocations expire at the end of the current semester; if you need an extension beyond it, please make this clear in your proposal.

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Priority Z Time Programme

Researchers can apply for LT observations in a Priority Z Time mode, outside of the usual semester-based rounds and Time Allocation Committees. We welcome Priority Z proposals from any active research astronomer. The intention is to provide a backup programme that fills the telescope queue during instrument downtime or periods of poor weather.

What is Priority Z time?

We define Priority Z time as time when there is no A, B or C-ranked science group available for the scheduler to pick, so the telescope would otherwise sit idle. This can happen during poor seeing around full moon, or during instrument failures. We estimate roughly 10–15 hours of such time per month, though this varies significantly.

How to apply

Applications can be submitted at any time using only the Phase 1 proposal form. Science and technical justifications are provided as plain text: keep them clear and concise, but include enough detail of the scientific objectives and methodology for the peer-review process to understand the aim and assess conflicts with existing allocations. Beyond the usual telescope/instrument configuration and integration requirements, the technical case should make clear how the observations exploit the limited, sporadic and potentially poor observing conditions available.

Allocations typically remain valid for two years from acceptance. Please include any information about date ranges or other constraints that would limit the data's usefulness — in particular, state clearly in the science case the range of semesters you want your programme to be active for.