Jeremiah Horrocks - Astronomical Observations

Astronomical Observations

Now committed to the study of astronomy, Horrocks began to build up a collection of astronomical books and equipment. In 1638 he bought the best telescope he could find, having found the cheap toy one he had bought some years earlier invaluable. As nearby Liverpool was a seafaring town, navigational instruments such as the astrolabe and cross staff were relatively easy to obtain. There was, at this time, no market for more specialised astronomical instruments and so his only option was to make his own. As luck would have it, he was well placed to do this as his father and uncles were watchmakers with the tools and expertise in producing accurate instruments. It seems likely that he would have helped with the family business during the daylight hours and, in return, the watchmakers in his family advised and assisted him with the design and construction of instruments to study the stars at night. He obtained a three foot radius astronomicus (a development of the cross staff with two movable sights on the cross piece) which he used to measure the angle between two stars, but by January 1637 he had come up against the limitations of this instrument and had built himself a larger version, eleven feet in length, in order to measure the angles more accurately. He read most of the astronomical treatises of his day, found the weaknesses in them and was suggesting new lines of research by the age of seventeen.

The traditional view is that, when he left home, he supported himself financially by holding a curacy in Much Hoole, near Preston in Lancashire, but there is little evidence for this and it is more likely he was a tutor to the Stones' children. According to local tradition in Much Hoole, he lived at Carr House, within the Bank Hall Estate, Bretherton. Carr House was a substantial property owned by the Stones family who were prosperous farmers and merchants, and Horrocks was probably a tutor for the Stones' children.