The sweep
Caroline Herschel sweeps the sky in zones with a small Newtonian, looking for nebulae and for anything that has moved. On 1 August 1786 she finds a faint comet. She writes the position. She tells William. The comet is hers to report.
The garden is also his observatory. The labor is shared and not interchangeable. A salary from George III later names her assistant. The comet does not wait for the salary.
ASTRONOMY
A comet is not a guest star. It moves against the fixed lamps. The method is the sweep: cover sky, notice what does not belong to last night’s map. Mitchell’s smear on Nantucket is another century, another roof, the same office of noticing.
Question
Who counts as the observer, when the house has two telescopes?