Two other important scientists were working in Oxford at this time; Edmond Halley and James Bradley. Halley had been appointed to the Savilian chair of geometry at Oxford in 1704 and had been appointed Astronomer Royal in 1720. Bradley had been appointed to the Savilian chair of astronomy at Oxford in 1721. Bliss attended lectures by Bradley but :-
Rather curiously, his name does not appear on the list of Pembroke College men who attended Bradley's courses, and one wonders how many other people attended without their names appearing in the surviving lists.Following the death of Halley in January 1742, Bradley applied for the position of Astronomer Royal and Bliss applied for the Savilian chair of geometry. Bliss was supported for this post by Bradley, and also by (among others) George Parker, the second earl of Macclesfield, and by William Jones. Bliss was appointed and took up the position on 18 February 1742. Following this he set up instruments in Oxford creating the fourth observatory in the city. He was elected a fellow of the Royal Society in May of 1742.
Bradley was successful in his application to succeed Halley as Astronomer Royal. One consequence of this was that he moved to Greenwich and Bliss now began a correspondence with Bradley which lasted 20 years until Bradley's death. Of course the journey from Oxford to Greenwich was not too difficult and he frequently visited Bradley at Greenwich. In addition Bliss undertook astronomical work with George Parker, the second earl of Macclesfield, who had established an observatory at Shirburn Castle. Bliss supplied Bradley with data gained from observing Jupiter's moons and collaborated with Bradley and the Earl of Macclesfield in making observations of the comet of 1745.
Bliss, of course, was Savilian professor of geometry at Oxford so, although his research interests were mainly in astronomy, he also taught mathematics at Oxford. McConnell writes :-
A notice for his lectures advertised courses in arithmetic, algebra, and plane and spherical trigonometry, with the use of logarithms and surveying instruments. He accepted between six and ten students in each class; they had to attend three times a week, for not less than one hour daily. He charged 2 guineas for each course, which lasted about three months, another half guinea being payable for every month the course lasted thereafter.By 1761 Bradley's health was deteriorating and he was not well enough to undertake the important observations of the transit of Venus on 6 June 1761. Bliss undertook these observations which he sent to the Royal Society. In 1762 Bradley died and so the position of Astronomer Royal became vacant. Bliss applied for the position and was duly appointed on 26 August 1762. It seems slightly ironical, but Bliss seems to have been more productive in astronomy research when he was the professor of geometry than when he was Astronomer Royal. Of course he was nearly 62 years of age when appointed and he only held the post for two years before his death so had relatively little time to make a mark :-
As he had completed no major researches in that time, his Greenwich observations were not published until 1805, when Thomas Hornsby included them as a supplement to his edition of the observations of James Bradley.He had a great interest in improving clocks, which he saw as important to improve astronomical measurements. This was a period when clocks were proving to be the solution to the longitude problem and Harrison's clock H4 was being tested during his time in Greenwich. Nevil Maskelyne was also trying to win the longitude prize using the lunar distance method. Bliss was one of three leading astronomers to examine the instruments that Maskelyne took to St Helena in 1763-64 as part of the longitude project. He also made observations of an annular eclipse visible at Greenwich on 1 April 1764.
J Fauvel, R Flood and R Wilson explain in  events which followed the death of Bliss:-
We must, however, assume that Bliss continued to teach in Oxford after his appointment as Astronomer Royal, for on 21 May 1765, his enterprising widow launched what one assumes to have been a continuation of his popular lectures, delivered by Bradley's Savilian astronomical successor, Thomas Hornsby, 'for the Entertainment of ladies and others'. Mrs Bliss was clearly the driving force behind the special lecture given in the Bodleian Library tower above the Schools quadrangle, for her name heads the published prospectus as organizer, taking precedence over Professor Hornsby who merely delivered it, and stipulating that the admission fee would be by ticket for half a crown. One assumes that the ladies who attended were well off, for in 1765 a halfcrown would have maintained a labourer's entire family for a couple of days.
Article by: J J O'Connor and E F Robertson