On his return home he settled at Westbury, where he erected an altazimuth by Troughton, with a two-and-a-half-foot circle.
We saw that the altazimuth employed at Upsala had no lenses.
The observations with the altazimuth are rather more complicated than those with the transit circle.
The altazimuth can thus determine the altitude and azimuth of objects, hence the name.
A most important step taken by Airy was the construction of an altazimuth.
The third day he had a full day's work on the calculations, followed by a night duty with the altazimuth.
This pillar is the support of Airy's altazimuth, and very nearly marks the place where Flamsteed set up his original sextant.
For many years the instruments in regular use were two only, the transit circle and the altazimuth.