The chronometric observatories of colonial India were, in a sense, both literal and figurative time machines. In the eighteenth century it became possible to think that the local structure of time provided access to its global structure – that clocks provided privileged access to universal history, both morally and practically. As an example of this process, I discuss the history of the Madras Observatory, a chronometric station built in 1791 under the rule of the East India Company in India to provide ephemerides and time signals to sailors and revenue surveyors throughout the Madras Presidency. Both revenue collection and the empire's extractive trade required ephemerides and chronometric data, which in turn depended on the astronomical regulation of chronometers. But measuring the variation in the measuring instruments themselves was a laborious process. To meet the demand, the Observatory employed specialised scribes, experts in jyotiśāstra [Sanskrit astral science], as observers and computers. The Brahmins carry and maintain modern instruments, but are fully identified with an ancient past by the Company’s astronomers, who styled themselves as continuing the astral sciences in the subcontinent. Colonial chronometry meant giving the modern observatory sciences an autochthonous ancient prestige, while at the same time tying the Brahmins to the instruments they were hired to operate.