There are different methods of observation that can be employed by the astronomer to determine position. Bennett (1979) explains the techniques of vertical circle observations for the determination of timed altitudes, horizontal circle observations for determination of timed azimuths and altazimuth observations.

 

The technique used to complete the observations to determine position was  the altazimuth observation technique. This method involves observing a star pass over the intersection of the cross hairs and noting the time when this occurs.

 

However before these observations could be taken the instrument had to be orientated with known celestial objects. This required computations to predict the position of a known star at a designated time. The star would have to be viewed then the instrument’s horizontal circle orientated to the predicted value (Bennett, 1979). This needs to be checked to another known star, this will show if any error is present in the calculations or the instrument.

 

The observations included two arcs made to four unknown stars, face left and face right observations were made to each star over each arc Then two arcs were made to two other unknown stars, with the face left and face right observations made to each star. The altitudes are noted as adjusted because the Wild T2 vertical circle measures 90° at the horizontal and 0° at the vertical.

OBSERVATIONS

POSITIONAL ASTRONOMEY THROUGH THE AGES

BY

BENJAMIN JACKSON

Last Update 29/10/2008