But, as it came from the hands of the makers in 1849, the Oxford heliometer was incomparably the most powerful and perfect instrument in the world for the highest order of micrometric research.
Considerable angles with micrometric accuracy, that he resolved, when he should have the choice of a new telescope for the observatory, to secure some form of heliometer.
P. 419) suggested the division of the small speculum of a Cassegrain telescope and the production of double image by micrometric rotation of the semispecula in the plane passing through their axis.
His micrometric measurements of 2714 double stars were made from 1824 to 1837, and are contained in his principal work, Stellarum duplicium et multiplicium mensurae micrometricae (St Petersburg, 1837 seq.; a convenient summary of the results is given in vol.
It was the result of several years' careful study and micrometric measurement of the features shown by the moon.
The precision of his earlier work is evidenced by his Micrometric Measurements of the Elementary Parts of Man and Animals (Leipzig, 1834).
Fraunhofer, Dorpat, 1825), and was an enormous advance upon all previous telescopes for micrometric research.
Provided the segments retain the same relative positions to each other as before the glass was cut); (2) that if the segments are separated in any direction two images of the object viewed will be produced; (3) that the most convenient direction of separation for micrometric purposes is to slide these straight edges one along the other as the figure on the margin (fig.
These facilities, coupled with the wide and fascinating field of research opened up by Sir William Herschel's discovery of the binary character of double stars, gave an impulse to micrometric research which has continued unabated to the present time.