Henry Kater's telescope Robert Benoist now Pygoplites diacanthus

now Pygoplites diacanthus

alis pentapetalis

Plate 14 figure 2 from the paper 'Sketches and descriptions of three simple instruments for drawing architecture and machinery in perspective'

The church was built by Nicholas Hawksmoor between 1716 and 1731

View of No 7 Angel Court

Henry Kater's telescope Robert Benoist now Pygoplites diacanthusTelescope used by Henry Kater for pendulum observations. Geodesist and metrologist Henry Kater (1777 1835) invented Kater's pendulum in 1817 which enabled the strength of gravity to be determined. This sight was used to view the pendulum during observations in order to avoid parallax error. ca. 1820