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3 Software and operations


Five software modules have been implemented in order to achieve a high degree of automation for TAROT-1 ([Bringer et al. 1999]). The REQUESTOR and MAJORDOME softwares are in charge of the request processing and of the scheduling of the telescope, using an optimised timeline ([Bringer et al. 1999]). The CONTROL software is in charge of the control and monitoring of the telescope, and sends orders to the CAMERA software, which in turn produces a FITS frame with the raw data. The TAITAR software produces a list of sources, astrometrically and photometrically calibrated.

TAROT functions in either of two operating modes. In routine mode, requests from the database are normally processed, following a timeline computed by the MAJORDOME. Whenever an alert occurs (e.g. a GRB position from the GCN), the alert mode is activated, and the telescope slews in less than 3 s (depending on the amplitude of the move), to the new target. Including the time needed by the GCN to compute the source position (4.5 s; [Barthelmy 1998]), and the INTERNET delay (0.5 s), TAROT begins its observations 8 s after the burst onset. At the same time, follow-up observations are inserted in the timeline for the remaining of this alert night and the following nights and a new schedule is computed by the MAJORDOME. BATSE error boxes will be observed as a mosaic of observations, a process which will take less than five minutes with the next camera. However, about once a year, it will happen that the right source position will be observed during the first observation, resulting in a simultaneous BATSE/TAROT observation. For the other satellites, including HETE-II, the fov of TAROT-1 is large enough to contain the full error box. This software chain allows TAROT-1 to produces without any human intervention, an image of the area of interest, including a list of sources, their variability, extension, etc. in few minutes. These products will be rapidly disseminated, in order to allow for fast follow-up observations at larger facilities.

Another interesting feature of TAROT-1 is its ability to compute a map of the cloud coverage of the sky, from the observation of evenly spaced reference stars. This greatly enhance the throughput of TAROT-1, since TAROT can observe even if we have a partial coverage, or a region free of clouds. In any case, the large fov of TAROT allows the validation of each individual image, even when the sky is partially covered.



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