|Place of work||Greenwich|
||10 Aug 1825 – 1852, May 29|
|Posts||1825, Aug 10
||Computer / Extra Assistant (established 1 Jan 1831)|
||Post retitled as Fourth Assistant
|Died||1852, May 29
|Family connections||Son William Ellis, Computer (1841–1852), Assistant (1853–1893)|
|Known addresses||1837||Trafalgar Road (the whole property at £30 a year (RGO6/42/231))|
|1845–1852||6 Cottage Place (renamed c.1899 as 65 Dutton Street, since demolished)|
When John Pond took on two extra staff at Greenwich in 1825, he acted on the advice of his Pocklington born assistant William Richardson and recruited William Rogerson who also came from Pocklington together with Thomas Ellis who came from nearby York. Their arrival meant that for the next twenty years, half of the Astronomical Assistants working for the Astronomer Royal were Yorkshire men. Whilst described by Pond in 1835 as having come from a school in Yorkshire (RGO6/72/223), he was described many years later in his son William’s obituaries as having being in commercial work.
Ellis and Rogerson were paid the same initial salary of £100 a year. Unlike Richardson and Thomas Glanville Taylor who were recruited by Pond in 1822, Ellis and Rogerson received no housing allowance. Nor were they eligible for the triennial pay rises that were awarded to the other assistants. They did however receive an allowance for coal and candles of £20 a year. When Airy took over as Astronomer Royal in 1835, the £20 coal and candles allowance became a £20 rent allowance. At that time, Ellis had three living children whose ages ranged from two to seven years (RGO6/72/224).
Ellis was described by Pond in 1835 as ‘a very useful, well behaved respectable man’ and more able than Rogerson. His role at the Observatory at that time was threefold: to observe with any of the instruments, undertake any computations and to keep the books (RGO6/72/223). Under Airy, his role was to assist John Henry Belville with the Transit Instrument, the reductions of the transits, the rating of the clocks, the testing of chronometers for the Navy, and the Time Ball. In 1845, following Richardson’s suspension and dismissal, he rose up the ranks to Third Assistant and had his salary increased from £100 to £150 a year. Following his death in service in 1852, he was replaced by John Henderson.