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Reactive Time Programme

IMPORTANT: Note to Schools, school children, and non-professional astronomers. Please be aware that Reactive Time proposals should only be submitted by research astronomers. These proposals are assessed and allocated for their contribution to international astrophysical research. Those affiliated with schools and colleges should generally apply for time through the National Schools' Observatory 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 (few days) access to LT observations.

Time on the LT is allocated by several Telescope Allocation Groups (TAGs). Not all have decided to use this REACTIVE mechanism. The TAGs that are 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 (see the Contact Us link on the sidebar) to discuss your project. We may still be able to accommodate your request.

use Reactive Time form

Rules of Use

  • Proposals will be accepted in two broad categories:

    • Test Observations: feasibility studies for full proposals to be submitted in future 'normal' semester-based application rounds. In this case some level of urgency should be demonstrated in the proposal. Short projects that are not urgent should be the subject of a full proposal submitted through the normal semester-based system. Multiple proposals making up a larger single project will not be accepted.
    • Unforeseen or Rare Targets of Opportunity: these include observations of newly-discovered targets or observations in support of existing projects on other telescopes. Targets which qualify are those which were not anticipated prior to the most recent proposal deadline: they were either totally unforseen or they are a rare event with a typical discovery rate of less than 1 per year. Target-of-opportunity programmes aimed at more common transient phenomena should be the subject of proposals submitted through the normal PATT or JMU applications system.
  • The intent of the reactive time programme is to increase the flexibility of the time allocation process and to take full advantage of the robotic nature of the LT. The Reactive Time programme complements the normal PATT and JMU time allocation process; it is therefore unlikely that time will be awarded to a proposal that could have been submitted through the traditional semester-based process. Similarly, we generally do NOT award Reactive time to PATT, CAT or JMU proposals that have simply run out of time in an existing semester. If this is the case, users are encouraged to contact the LT Support Astronomer to discuss the status of their project, rather than submit a Reactive proposal requesting 'top-up time'.
  • Proposals can be sent in at any time. They will be assessed by the appropriate TAG, or a subset of the TAG, as soon as possible after receipt. If accepted, the project will be given a rank in the current project queue depending on science rating relative to existing programmes and urgency. The probability that the observations are done and the timescale on which they are completed will depend on this rank and cannot be guaranteed, but it is likely to be a minimum of one working day.
  • Applications should be made using ONLY the web-based application form linked at the top of this page. To facilitate rapid processing of your proposal, please ensure that the scientific and technical cases are clear and concise. Proposals are entered into the web form as plain text. If your submission fails, please try again using a different web browser or contact the LT Support Astronomer (see the Contact Us link on the sidebar).
  • By default Reactive Time allocations expire at the end of the current semester. If extension beyond the current semester is required, please make this clear in your proposal.