A telescope design and performance analysis tool: the Mission-Quality criterion

摘要

We present a quality criterion for telescopes based on the fulfillment of observation needs as defined by a client. It is intended for the pre-conception and broad control level. The criterion is built from the fidelity measure by limiting the spatial scales taken into account to the scales useful to the proper imaging of the detail of interest. By construction this mono-dimensional criterion allows trade-off between spatial and radiometric resolution. The comparison of different design strategies is also possible, for example between undersampled large aperture telescopes and well sampled smaller telescopes. It can also be used to predict the usefulness of each available telescope for a given observational purpose. Being global, the criterion requires only high-level specifications, thus allowing the client to exercise a greater degree of control over the instrument definition. We present here a pre-calibration of the mission quality criteria enabling to give an absolute quality value for the telescope and to determine whether the observation mission is fulfilled. A comparison of test-case telescopes is then made by varying several design parameters.